5.2: Sound and Audio, Image and Graphics, Animation and Video
Introduction
The following sections describe various types of data that you might find, in addition to static graphics data, in multimedia files.
Activity Details
Computer animation lies somewhere between the motionless world of still images and the real-time world of video images. All of the animated sequences seen in educational programs, motion CAD renderings, and computer games are computer-animated (and in many cases, computer-generated) animation sequences.
Traditional cartoon animation is little more than a series of artwork cells, each containing a slight positional variation of the animated subjects. When a large number of these cells is displayed in sequence and at a fast rate, the animated figures appear to the human eye to move.
A computer-animated sequence works in exactly the same manner, i.e a series of images is created of a subject; each image contains a slightly different perspective on the animated subject. When these images are displayed (played back) in the proper sequence and at the proper speed (frame rate), the subject appears to move.
Computerized animation is actually a combination of both still and motion imaging. Each frame, or cell, of an animation is a still image that requires compression and storage. An animation file, however, must store the data for hundreds or thousands of animation frames and must also provide the information necessary to play back the frames using the proper display mode and frame rate.
Animation file formats are only capable of storing still images and not actual video information. It is possible, however, for most multimedia formats to contain animation information, because animation is actually a much easier type of data than video to store.
The image-compression schemes used in animation files are also usually much simpler than most of those used in video compression. Most animation files use a delta compression scheme, which is a form of Run-Length Encoding that stores and compresses only the information that is different between two images (rather than compressing each image frame entirely). RLE is relatively easy to decompress on the fly.
Storing animations using a multimedia format also produces the benefit of adding sound to the animation (what’s a cartoon without sound?). Most animation formats cannot store sound directly in their files and must rely on storing the sound in a separate disk file which is read by the application that is playing back the animation.
Animations are not only for entertaining kids and adults. Animated sequences are used by CAD programmers to rotate 3D objects so they can be observed from different perspectives; mathematical data collected by an aircraft or satellite may be rendered into an animated fly-by sequence. Movie special effects benefit greatly by computer animation.
Digital Video
One step beyond animation is broadcast video. Your television and video tape recorder are a lot more complex than an 8mm home movie projector and your kitchen wall. There are many complex signals and complicated standards that are involved in transmitting those late-night reruns across the airwaves and cable. Only in the last few years has a personal computer been able to work with video data at all.
Video data normally occurs as continuous, analog signals. In order for a computer to process this video data, we must convert the analog signals to a non-continuous, digital format. In a digital format, the video data can be stored as a series of bits on a hard disk or in computer memory.
The process of converting a video signal to a digital bitstream is called analog-to-digital conversion (A/D conversion), or digitizing. A/D conversion occurs in two steps:
- Sampling captures data from the video stream.
- Quantizing converts each captured sample into a digital format.
Each sample captured from the video stream is typically stored as a 16-bit integer. The rate at which samples are collected is called the sampling rate. The sampling rate is measured in the number of samples captured per second (samples/second). For digital video, it is necessary to capture millions of samples per second.
Quantizing converts the level of a video signal sample into a discrete, binary value. This value approximates the level of the original video signal sample. The value is selected by comparing the video sample to a series of predefined threshold values. The value of the threshold closest to the amplitude of the sampled signal is used as the digital value.
A video signal contains several different components which are mixed together in the same signal. This type of signal is called a composite video signal and is not really useful in high- quality computer video. Therefore, a standard composite video signal is usually separated into its basic components before it is digitized.
The composite video signal format defined by the NTSC (National Television Standards Committee) color television system is used in the United States. The PAL (Phase Alternation Line) and SECAM (Sequential Coleur Avec Memoire) color television systems are used in Europe and are not compatible with NTSC. Most computer video equipment supports one or more of these system standards.
The components of a composite video signal are normally decoded into three separate signals representing the three channels of a color space model, such as RGB, YUV, or YIQ. Although the RGB model is quite commonly used in still imaging, the YUV, YIQ, or YCbCr models are more often used in motion-video imaging. TV practice uses YUV or similar color models because the U and V channels can be downsampled to reduce data volume without materially degrading image quality.
Once the video signal is converted to a digital format, the resulting values can be represented on a display device as pixels. Each pixel is a spot of color on the video display, and the pixels are arranged in rows and columns just as in a bitmap. Unlike a static bitmap, however, the pixels in a video image are constantly being updated for changes in intensity and color. This updating is called scanning, and it occurs 60 times per second in NTSC video signals (50 times per second for PAL and SECAM).
A video sequence is displayed as a series of frames. Each frame is a snapshot of a moment in time of the motion-video data, and is very similar to a still image. When the frames are played back in sequence on a display device, a rendering of the original video data is created. In real- time video the playback rate is 30 frames per second. This is the minimum rate necessary for the human eye to successfully blend each video frame together into a continuous, smoothly moving image.
A single frame of video data can be quite large in size. A video frame with a resolution of 512 x 482 will contain 246,784 pixels. If each pixel contains 24 bits of color information, the frame will require 740,352 bytes of memory or disk space to store. Assuming there are 30 frames per second for real-time video, a 10-second video sequence would be more than 222 megabytes in size! It is clear there can be no computer video without at least one efficient method of video data compression.
There are many encoding methods available that will compress video data. The majority of these methods involve the use of a transform coding scheme, usually employing a Fourier or Discrete Cosine Transform (DCT). These transforms physically reduce the size of the video data by selectively throwing away unneeded parts of the digitized information.
Transform compression schemes usually discard 10 percent to 25 percent or more of the original video data, depending largely on the content of the video data and upon what image quality is considered acceptable.
Usually a transform is performed on an individual video frame. The transform itself does not produce compressed data. It discards only data not used by the human eye. The transformed data, called coefficients, must have compression applied to reduce the size of the data even further. Each frame of data may be compressed using a Huffman or arithmetic encoding algorithm, or even a more complex compression scheme such as JPEG. This type of intraframe encoding usually results in compression ratios between 20:1 to 40:1 depending on the data in the frame. However, even higher compression ratios may result if, rather than looking at single frames as if they were still images, we look at multiple frames as temporal images.
In a typical video sequence, very little data changes from frame to frame. If we encode only the pixels that change between frames, the amount of data required to store a single video frame drops significantly. This type of compression is known as interframe delta compression, or in the case of video, motion compensation. Typical motion compensation schemes that encode only frame deltas (data that has changed between frames) can, depending on the data, achieve compression ratios upwards of 200:1. This is only one possible type of video compression method. There are many other types of video compression schemes, some of which are similar and some of which are different.
Digital Audio
All multimedia file formats are capable, by definition, of storing sound information. Sound data, like graphics and video data, has its own special requirements when it is being read, written, interpreted, and compressed. Before looking at how sound is stored in a multimedia format we must look at how sound itself is stored as digital data. All of the sounds that we hear occur in the form of analog signals. An analog audio recording system, such as a conventional tape recorder, captures the entire sound wave form and stores it in analog format on a medium such as magnetic tape.
Because computers are now digital devices it is necessary to store sound information in a digitized format that computers can readily use. A digital audio recording system does not record the entire wave form as analog systems do (the exception being Digital Audio Tape [DAT] systems). Instead, a digital recorder captures a wave form at specific intervals, called the sampling rate. Each captured wave-form snapshot is converted to a binary integer value and is then stored on magnetic tape or disk.
Storing audio as digital samples is known as Pulse Code Modulation (PCM). PCM is a simple quantizing or digitizing (audio to digital conversion) algorithm, which linearly converts all analog signals to digital samples. This process is commonly used on all audio CD-ROMs.
Differential Pulse Code Modulation (DPCM) is an audio encoding scheme that quantizes the difference between samples rather than the samples themselves. Because the differences are easily represented by values smaller than those of the samples themselves, fewer bits may be used to encode the same sound (for example, the difference between two 16-bit samples may only be four bits in size). For this reason, DPCM is also considered an audio compression scheme.
One other audio compression scheme, which uses difference quantization, is Adaptive Differential Pulse Code Modulation (ADPCM). DPCM is a non-adaptive algorithm. That is, it does not change the way it encodes data based on the content of the data. DPCM uses the sample number of bits to represent every signal level. ADPCM, however, is an adaptive algorithm and changes its encoding scheme based on the data it is encoding. ADPCM specifically adapts by using fewer bits to represent lower-level signals than it does to represent higher-level signals. Many of the most commonly used audio compression schemes are based on ADPCM.
Digital audio data is simply a binary representation of a sound. This data can be written to a binary file using an audio file format for permanent storage much in the same way bitmap data is preserved in an image file format. The data can be read by a software application, can be sent as data to a hardware device, and can even be stored as a CD-ROM.
The quality of an audio sample is determined by comparing it to the original sound from which it was sampled. The more identical the sample is to the original sound, the higher the quality of the sample. This is similar to comparing an image to the original document or photograph from which it was scanned.
The quality of audio data is determined by three parameters:
- Sample resolution
- Sampling rate
- Number of audio channels sampled
The sample resolution is determined by the number of bits per sample. The larger the sampling size, the higher the quality of the sample. Just as the apparent quality (resolution) of an image is reduced by storing fewer bits of data per pixel, so is the quality of a digital audio recording reduced by storing fewer bits per sample. Typical sampling sizes are eight bits and 16 bits.
The sampling rate is the number of times per second the analog wave form was read to collect data. The higher the sampling rate, the greater the quality of the audio. A high sampling rate collects more data per second than a lower sampling rate, therefore requiring more memory and disk space to store. Common sampling rates are 44.100 kHz (higher quality), 22.254 kHz (medium quality), and 11.025 kHz (lower quality). Sampling rates are usually measured in the signal processing terms hertz (Hz) or kilohertz (kHz), but the term samples per second (samples/ second) is more appropriate for this type of measurement.
A sound source may be sampled using one channel (monaural sampling) or two channels (stereo sampling). Two-channel sampling provides greater quality than mono sampling and, as you might have guessed, produces twice as much data by doubling the number of samples captured. Sampling one channel for one second at 11,000 samples/second produces 11,000 samples. Sampling two channels at the same rate, however, produces 22,000 samples/second.
The amount of binary data produced by sampling even a few seconds of audio is quite large. Ten seconds of data sampled at low quality (one channel, 8-bit sample resolution, 11.025 samples/second sampling rate) produces about 108K of data (88.2 Kbits/second).
Adding a second channel doubles the amount of data to produce nearly a 215K file (176 Kbits/ second). If we increase the sample resolution to 16 bits, the size of the data doubles again to 430K (352 Kbits/second). If we now increase the sampling rate to 22.05 Ksamples/second, the amount of data produced doubles again to 860K (705.6 Kbits/second). At the highest quality generally used (two channels, 16-bit sample resolution, 44.1 Ksamples/second sampling rate), our 10 seconds of audio now requires 1.72 megabytes (1411.2 Kbits/second) of disk space to store.
Consider how little information can really be stored in 10 seconds of sound. The typical musical song is at least three minutes in length. Music videos are from five to 15 minutes in length. A typical television program is 30 to 60 minutes in length. Movie videos can be three hours or more in length. We’re talking a lot of disk space here.
One solution to the massive storage requirements of high-quality audio data is data compression. For example, the CD-DA (Compact Disc-Digital Audio) standard performs mono or stereo sampling using a sample resolution of 16 bits and a sampling rate of 44.1 samples/ second, making it a very high-quality format for both music and language applications. Storing five minutes of CD-DA information requires approximately 25 megabytes of disk space--only half the amount of space that would be required if the audio data were uncompressed.
Audio data, in common with most binary data, contains a fair amount of redundancy that can be removed with data compression. Conventional compression methods used in many archiving programs (zoo and pkzip, for example) and image file formats don’t do a very good job of compressing audio data (typically 10 percent to 20 percent). This is because audio data is organized very differently from either the ASCII or binary data normally handled by these types of algorithms.
Audio compression algorithms, like image compression algorithms, can be categorized as lossy and lossless. Lossless compression methods do not discard any data. The decompression step produces exactly the same data as was read by the compression step. A simple form of lossless audio compression is to Huffman-encode the differences between each successive 8-bit sample. Huffman encoding is a lossless compression algorithm and, therefore the audio data is preserved in its entirety.
Lossy compression schemes discard data based on the perceptions of the psychoacoustic system of the human brain. Parts of sounds that the ear cannot hear, or the brain does not care about, can be discarded as useless data.
An algorithm must be careful when discarding audio data. The ear is very sensitive to changes in sound. The eye is very forgiving about dropping a video frame here or reducing the number of colors there. The ear, however, notices even slight changes in sounds, especially when specifically trained to recognize audial infidelities and discrepancies. However, the higher the quality of an audio sample, the more data will be required to store it. As with lossy image compression schemes, at times you’ll need to make a subjective decision between quality and data size.
Audio
There is currently no “audio file interchange format” that is widely used in the computer-audio industry. Such a format would allow a wide variety of audio data to be easily written, read, and transported between different hardware platforms and operating systems.
Most existing audio file formats, however, are very machine-specific and do not lend themselves to interchange very well. Several multimedia formats are capable of encapsulating a wide variety of audio formats, but do not describe any new audio data format in themselves.
Many audio file formats have headers just as image files do. Their header information includes parameters particular to audio data, including sample rate, number of channels, sample resolution, type of compression, and so on. An identification field (“magic” number) is also included in several audio file format headers.
Several formats contain only raw audio data and no file header. Any parameters these formats use are fixed in value and therefore would be redundant to store in a file header. Stream- oriented formats contain packets (chunks) of information embedded at strategic points within the raw audio data itself. Such formats are very platform-dependent and would require an audio file format reader or converter to have prior knowledge of just what these parameter values are.
Most audio file formats may be identified by their file types or extensions. Some common sound file formats are:
- .AU Sun Microsystems
- .SND NeXT
- HCOM Apple Macintosh
- .VOC SoundBlaster
- .WAV Microsoft Waveform
- AIFF Apple/SGI
- 8SVX Apple/SGI
A multimedia format may choose to either define its own internal audio data format or simply encapsulate an existing audio file format. Microsoft Waveform files are RIFF files with a single Waveform audio file component, while Apple QuickTime files contain their own audio data structures unique to QuickTime files.
MIDI Standard
Musical Instrument Digital Interface (MIDI) is an industry standard for representing sound in a binary format. MIDI is not an audio format, however. It does not store actual digitally sampled sounds. Instead, MIDI stores a description of sounds, in much the same way that a vector image format stores a description of an image and not image data itself.
Sound in MIDI data is stored as a series of control messages. Each message describes a sound event using terms such as pitch, duration, and volume. When these control messages are sent to a MIDI-compatible device (the MIDI standard also defines the interconnecting hardware used by MIDI devices and the communications protocol used to interchange the control information) the information in the message is interpreted and reproduced by the device.
MIDI data may be compressed, just like any other binary data, and does not require special compression algorithms in the way that audio data does.
Conclusion
The activity introduced the various data formats that are possible in a multimedia, it also explained the conversions possible, e.g. sampling, quantization and animations
Assessment
1.What is digital conversion? is a very useful feature that converts an analog voltage on a pin to a digital number. By converting from the analog world to the digital world, we can begin to use electronics to interface to the analog world around us.
e.g. Analog-to-digital conversion is an electronic process in which a continuously variable (analog) signal is changed, without altering its essential content, into a multi-level (digital) signal.
The input to an analog-to-digital converter (ADC) consists of a voltage that varies among a theoretically infinite number of values. Examples are sine waves, the waveforms representing human speech, and the signals from a conventional television camera. The output of the ADC, in contrast, has defined levels or states. The number of states is almost always a power of two -- that is, 2, 4, 8, 16, etc. The simplest digital signals have only two states, and are called binary. All whole numbers can be represented in binary form as strings of ones and zeros.
2.Explain MIDI
MIDI (Musical Instrument Digital Interface) is a protocol designed for recording and playing back music on digital synthesizers that is supported by many makes of personal computer sound cards. Originally intended to control one keyboard from another, it was quickly adopted for the personal computer. Rather than representing musical sound directly, it transmits information about how music is produced. The command set includes note-ons, note-offs, key velocity, pitch bend and other methods of controlling a synthesizer. The sound waves produced are those already stored in a wavetable in the receiving instrument or sound card.


5.6: Application of LCR and Crown Class in Forest Management
5.6 Application of LCR and Crown Class in Forest Management
Live crown ratio and crown class are descriptors of tree crown characteristics and indicators of tree vigor. One of the ways that foresters use these terms is to communicate decisions about stand management. For example, let’s say a forester wants to improve stand vigor by doing the following:
- reduce incidence of mortality by reducing tree density
- concentrate growth on the healthiest trees
- remove trees with evidence of disease
These are general concepts and overall directions for the stand. But how does one decide which individual trees to cut or leave, and how does one communicate that information, especially to a crew of people marking the trees? Each acre of ground and each individual tree in the forest are unique. Until one actually walks through the entire stand, decisions about individual trees cannot be made. So a set of specific directions describing cut and leave trees must be written to more clearly explain a forester’s intentions.
Therefore, in writing a prescription for the stand management described above, a forester would use standard terms to describe the intended management outcomes. For example, the following directions might be part of the marking directions.
- Reduce tree density to 75 Trees per acre. On average, space trees ≈ 24’ apart.
- Leave primarily Dominant trees; second preference is for Codominant trees with LCR > 40%.
- Favor trees with intact crowns.
- Remove trees with evidence of disease or deformity.
- Remove primarily Intermediate and Suppressed trees.
- Remove primarily trees with LCR < 30%.
In this way, the person making the cut and leave decisions on the ground has a much clearer idea of how to achieve the objective to “improve stand vigor.”


6.2: Case Study 3- Pregnant Adult Client
Initial Assessment Data
- Biographical data: Pregnant adult client (age 32)
- Reason for seeking care: Shortness of breath at a prenatal visit
- History of health/illness: 36 weeks pregnant
- Past history: No medications, no illnesses
Vital Sign Measurements
1430 hrs, August 14, 2018
- T 37.1°C axilla
- RR 14 (shallow breathing)
- P 92 (radial), regular rhythm, 2+ force, Sp02 97%
- BP 134/90 mm Hg (right arm, sitting position)
Baseline vital signs (pre-pregnancy)
- T 36.7°C axilla
- RR 14
- P 84, regular rhythm, 2+ force, Sp02 97%
- BP 124/74 mm Hg (right arm)
Think about the client data and try to answer the following questions.
- What needs to be considered when interpreting the vital signs findings of this pregnant client?
- Which vital sign findings are considered abnormal for this pregnant client? What medical terminology is used to define/label these findings?
Go to the next page to check your answers.


1.4: Preventing Foodborne Illness
Food-handling and Storage Procedures
Proper food handling and storage can prevent most foodborne illnesses. In order for pathogens to grow in food, certain conditions must be present. By controlling the environment and conditions, even if potentially harmful bacteria are present in the unprepared or raw food, they will not be able to survive, grow, and multiply, causing illness.
There are six factors that affect bacterial growth, which can be referred to by the mnemonic FATTOM :
- F ood
- A cid
- T emperature
- T ime
- O xygen
- M oisture
Each of these factors contributes to bacterial growth in the following ways:
- Food: Bacteria require food to survive. For this reason, moist, protein-rich foods are good potential sources of bacterial growth.
- Acid: Bacteria do not grow in acidic environments. This is why acidic foods like lemon juice and vinegar do not support the growth of bacteria and can be used as preservatives
- Temperature: Most bacteria will grow rapidly between 4°C and 60°C (40°F and 140°F). This is referred to as the danger zone (see the section below for more information on the danger zone).
- Time: Bacteria require time to multiply. When small numbers of bacteria are present, the risk is usually low, but extended time with the right conditions will allow the bacteria to multiply and increase the risk of contamination
- Oxygen: There are two types of bacteria. Aerobic bacteria require oxygen to grow, so will not multiply in an oxygen-free environment such as a vacuum-packaged container. Anaerobic bacteria will only grow in oxygen-free environments. Food that has been improperly processed and then stored at room temperature can be at risk from anaerobic bacteria. A common example is a product containing harmful Clostridium botulinum (botulism-causing) bacteria that has been improperly processed during canning, and then is consumed without any further cooking or reheating.
- Moisture: Bacteria need moisture to survive and will grow rapidly in moist foods. This is why dry and salted foods are at lower risk of being hazardous.
Identifying Potentially Hazardous Foods (PHFs)
Foods that have the FATTOM conditions are considered potentially hazardous foods (PHFs) . PHFs are those foods that are considered perishable. That is, they will spoil or “go bad” if left at room temperature. PHFs are foods that support the growth or survival of disease-causing bacteria (pathogens) or foods that may be contaminated by pathogens.
Generally, a food is a PHF if it is:
- Of animal origin such as meat, milk, eggs, fish, shellfish, poultry (or if it contains any of these products)
- Of plant origin (vegetables, beans, fruit, etc.) that has been heat-treated or cooked
- Any of the raw sprouts (bean, alfalfa, radish, etc.)
- Any cooked starch (rice, pasta, etc.)
- Any type of soya protein (soya milk, tofu, etc.)
Table 2 identifies common foods as either PHF or non-PHF.
| PHF | Non-PHF |
|---|---|
| Chicken, beef, pork, and other meats | Beef jerky |
| Pastries filled with meat, cheese, or cream | Bread |
| Cooked rice | Uncooked rice |
| Fried onions | Raw onions |
| Opened cans of meat, vegetables, etc. | Unopened cans of meat, vegetables, etc. (as long as they are not marked with “Keep Refrigerated”) |
| Tofu | Uncooked beans |
| Coffee creamers | Cooking oil |
| Fresh garlic in oil | Fresh garlic |
| Fresh or cooked eggs | Powdered eggs |
| Gravy | Flour |
| Dry soup mix with water added | Dry soup mix |
The Danger Zone
One of the most important factors to consider when handling food properly is temperature. Table 3 lists the most temperatures to be aware of when handling food.
| Celsius | Fahrenheit | What happens? |
|---|---|---|
| 100° | 212° | Water boils |
| 60° | 140° | Most pathogenic bacteria are destroyed. Keep hot foods above this temperature. |
| 20° | 68° | Food must be cooled from 60°C to 20°C (140°F to 68°F) within two hours or less |
| 4° | 40° | Food must be cooled from 20°C to 4°C (68°F to 40°F) within four hours or less |
| 0° | 32° | Water freezes |
| –18° | 0° | Frozen food must be stored at −18°C (0°F) or below |
The range of temperature from 4°C and 60°C (40°F and 140°F) is known as the danger zone , or the range at which most pathogenic bacteria will grow and multiply.
Time-temperature Control of PHFs
Pathogen growth is controlled by a time-temperature relationship. To kill micro-organisms, food must be held at a sufficient temperature for a sufficient time. Cooking is a scheduled process in which each of a series of continuous temperature combinations can be equally effective. For example, when cooking a beef roast, the microbial lethality achieved at 121 minutes after it has reached an internal temperature of 54°C (130°F) is the same as if it were cooked for 3 minutes after it had reached 63°C (145°F).
Table 4 show the minimum time-temperature requirements to keep food safe. (Other time-temperature regimens might be suitable if it can be demonstrated, with scientific data, that the regimen results in a safe food.)
| Critical control point | Type of food | Temperature |
|---|---|---|
| Refrigeration | Cold food storage, all foods. | 4°C (40°F) or less |
| Freezing | Frozen food storage, all foods. | −18°C (0°F) or less |
| Freezing | Parasite reduction in fish intended to be served raw, such as sushi and sashimi | −20°C (−4°F) for 7 days or −35°C (−31°F) in a blast freezer for 15 hours |
| Cooking | Food mixtures containing poultry, eggs, meat, fish, or other potentially hazardous foods | Internal temperature of 74°C (165°F) for at least 15 seconds |
| Cooking | Rare roast beef | Internal temperature of 54°C to 60°C (130°F to 140°F) |
| Cooking | Medium roast beef | Internal temperature of 60°C to 65°C (140°F to 150°F) |
| Cooking | Pork, lamb, veal, beef (medium-well) | Internal temperature of 65°C to 69°C (150°F to 158°F) |
| Cooking | Pork, lamb, veal, beef (well done) | Internal temperature of 71°C (160°F) |
| Cooking | Poultry | Internal temperature of 74°C (165°F) for 15 seconds |
| Cooking | Stuffing in poultry | 74°C (165°F) |
| Cooking | Ground meat (Includes chopped, ground, flaked, or minced beef, pork, or fish) | 70°C (158°F) |
| Cooking | Eggs [1] | 63°C (145°F) for 15 seconds |
| Cooking | Fish [2] | 70°C (158°F) |
| Holding | Hot foods | 60°C (140°F) |
| Cooling | All foods | 60°C to 20°C (140°F to 68°F) within 2 hours and 20°C to 4°C (68°F to 40°F) within 4 hours |
| Reheating | All foods | 74°C (165°F) for at least 15 seconds |
The Top 10 List: Do’s and Don’ts
Figure 1 illustrates the top 10 improper food-handling methods and the percentage of foodborne illnesses they cause.
This section describes each food-handling practice outlined in the top 10 list and the ways to prevent each problem.
1. Improper cooling
Many people think that once a food has been properly cooked, all disease-causing organisms (pathogens) have been killed. This is not true. Some pathogens can form heat-resistant spores, which can survive cooking temperatures. When the food begins cooling down and enters the danger zone, these spores begin to grow and multiply. If the food spends too much time in the danger zone, the pathogens will increase in number to a point where the food will make people sick. That is why the cooling process is crucial. Cooked food must be cooled from 60°C to 20°C (140°F to 70°F) in two hours or less, AND then from 20°C to 4°C (70°F to 40°F) in four hours or less.
Even in modern walk-in coolers, large cuts of meat will not cool down properly. Neither will whole poultry. Even large pots (4 L/1 gal. or more) of soup, stews, gravy, etc., can take a day or more to cool to 4°C (40°F). However, you can cool these foods down quickly by using one or more of the following methods depending on the type of food being cooled:
- Place the food in shallow pans (with the food no deeper than 5 cm/2 in.) and put the pans in the cooler.
- When the food is cooling, do not tightly cover. Doing so only seals in the heat.
- Do not stack the shallow cooling pans during the cooling step. This will defeat the purpose of shallow panning by preventing cold air from reaching the food. You may need to add more shelves to your cooler.
- Cut large cuts of meat or whole poultry into smaller or thinner portions. Then place these portions into shallow pans for cooling.
- Use cooling wands or cooling sticks to cool foods quickly.
- Use rapid cooling equipment such as walk-in coolers with wire shelving and good air flow. Home-style refrigerators or reach-ins do not cool food well.
- Stir the food in a container placed in an ice-water bath.
- Use containers that help heat transfer, such as stainless steel or aluminum. Plastic does not transfer heat well.
- Use ice as an ingredient (e.g., in stews or soups).
- For large pots of cooked desserts (e.g., custard), divide it into serving sizes and then cool.
2. Advance preparation
Advance preparation is the cause of many food-poisoning outbreaks, usually because food has been improperly cooled. Often, foods that are prepared well before serving spend too much time in the danger zone. This may happen for one or more of the following reasons:
- The food is left out at room temperature too long.
- The food is not heated or reheated properly (to a high enough temperature), or not cooled properly.
- The food is brought in and out of the danger zone too many times (e.g., cooked, hot held, cooled, reheated, hot held, cooled, reheated again).
To prevent problems of advance preparation:
- Try to prepare all foods for same-day use and as close to serving time as possible.
- To prevent outside contamination of foods prepared in advance, cover them tightly after they have been properly cooled.
- Reheat leftovers only once. If leftovers are not consumed after being reheated, throw them out.
- For foods prepared and held refrigerated in the cooler for more than 24 hours, mark the date of preparation and a “serve by” date. Generally, PHFs should be thrown out if not used within three days from date they were made.
- If you must prepare foods in advance, be sure you properly cool and refrigerate them.
3. Infected person
Many people carry pathogens somewhere on or in their bodies without knowing it—in their gut, in their nose, on their hands, in their mouth, and in other warm, moist places. People who are carrying pathogens often have no outward signs of illness. However, people with symptoms of illness (diarrhea, fever, vomiting, jaundice, sore throat with a fever, hand infections, etc.) are much more likely to spread pathogens to food.
Another problem is that pathogens can be present in the cooked and cooled food that, if given enough time, can still grow. These pathogens multiply slowly but they can eventually reach numbers where they can make people sick. This means that foods that are prepared improperly, many days before serving, yet stored properly the entire time can make people sick.
Some pathogens are more dangerous than others (e.g., salmonella, E. coli, campylobacter). Even if they are only present in low numbers, they can make people very sick. A food handler who is carrying these kinds of pathogens can easily spread them to foods – usually from their hands. Ready-to-eat food is extra dangerous. Ready-to-eat food gets no further cooking after being prepared, so any pathogens will not be killed or controlled by cooking.
To prevent problems:
- Make sure all food handlers wash their hands properly after any job that could dirty their hands (e.g., using the toilet, eating, handling raw meats, blowing their nose, smoking).
- Food handlers with infected cuts on their hands or arms (including sores, burns, lesions, etc.) must not handle food or utensils unless the cuts are properly covered (e.g., waterproof bandage covered with a latex glove or finger cot).
- When using gloves or finger cots , food handlers must still wash their hands. As well, gloves or cots must be replaced if they are soiled, have a hole, and at the end of each day.
- Food handlers with infection symptoms must not handle utensils or food and should be sent home.
- Where possible, avoid direct hand contact with food – especially ready-to-eat foods (e.g., use plastic utensils plastic or latex gloves).
4. Inadequate reheating for hot holding
Many restaurants prepare some of menu items in advance or use leftovers in their hot hold units the next day. In both cases, the foods travel through the danger zone when they are cooled for storage and again when they are reheated.
Foods that are hot held before serving are particularly vulnerable to pathogens. In addition to travelling through the danger zone twice, even in properly operating hot hold units, the food is close to the temperature that will allow pathogens to grow.
To prevent problems:
- Do not use hot hold units to reheat food. They are not designed for this purpose. Instead, rapidly reheat to 74°C (165°F) (and hold the food at that temperature for at least 15 seconds before putting it in the hot hold unit. This will kill any pathogens that may have grown during the cool-down step and the reheat step.
- If using direct heat (stove top, oven, etc.), the temperature of the reheated food must reach at least 74°C (165°F) for at least 15 seconds within two hours. Keep a thermometer handy to check the temperature of the food.
- If using a microwave, rotate or stir the food at least once during the reheat step, as microwaves heat unevenly. As well, the food must be heated to at least 74°C (165°F) and then stand covered for two minutes after reheating before adding to the hot hold unit. The snapping and crackling sounds coming from food being reheated in a microwave do not mean the food is hot.
5. Improper hot holding
Hot hold units are meant to keep hot foods at 60°C (140°F) or hotter. At or above this temperature, pathogens will not grow. However, a mistake in using the hot hold unit can result in foods being held in the super danger zone – between 20°C and 49°C (70°F and 120°F), temperatures at which pathogens grow very quickly.
To prevent problems:
- Make sure the hot hold unit is working properly (e.g., heating elements are not burnt out; water is not too low in steam tables; the thermostat is properly set so food remains at 60°C (140°F) or hotter) Check it daily with a thermometer.
- Put only already hot (74°C/165°F) foods into the hot hold unit.
- Preheat the hot hold unit to at least 60°C (140°F) before you start putting hot foods into it.
- Do not use the hot hold unit to reheat cold foods. It is not designed for or capable of doing this rapidly.
- After the lunch or dinner rush, do not turn off the heat in the hot hold unit and then leave the food there to cool. This is very dangerous. When you do this, the food does not cool down. It stays hot in the super danger zone and lets pathogens grow quickly. Foods in hot hold units should be taken out of the units after the meal time is over and cooled right away.
6. Contaminated raw food or ingredient
We know that many raw foods often contain pathogens, yet certain foods are often served raw. While some people believe these foods served raw are “good for you,” the truth is that they have always been dangerous to serve or eat raw. Some examples include:
- Raw oysters served in the shell
- Raw eggs in certain recipes (e.g., Caesar salad, eggnog made from raw eggs)
- Rare hamburger
- Sushi/sashimi
- Steak tartare
These foods have caused many food-poisoning outbreaks. Always remember: you cannot tell if a food contains pathogens just by look, taste, or smell.
To prevent problems:
- Buy all your foods or ingredients from approved suppliers.
- If available, buy foods or ingredients from suppliers who also have food safety plans for their operations.
- Where possible, use processed or pasteurized alternatives (e.g., pasteurized liquid eggs).
- Never serve these types of foods to high-risk customers (e.g., seniors, young children, people in poor health, people in hospitals or nursing homes).
7. Unsafe source
Foods from approved sources are less likely to contain high levels of pathogens or other forms of contamination. Approved sources are those suppliers that are inspected for cleanliness and safety by a government food inspector. Foods supplied from unreliable or disreputable sources, while being cheaper, may contain high levels of pathogens that can cause many food-poisoning outbreaks.
Fly-by-night suppliers (trunk sales) often do not care if the product is safe to sell to you, but approved suppliers do! As well, many fly-by-night suppliers have obtained their product illegally (e.g., closed shellfish fisheries, rustled cattle, poached game and fish) and often do not have the equipment to properly process, handle, store, and transport the food safely.
Of particular concern is seafood from unapproved sources. Seafood, especially shellfish, from unapproved sources can be heavily contaminated with pathogens or poisons if they have been harvested from closed areas.
To prevent problems:
- Buy your food and ingredients from approved sources only. If you are not sure a supplier has been approved, contact your local environmental health officer. He or she can find out for you.
- Do not take the chance of causing a food-poisoning outbreak by trying to save a few dollars. Remember, your reputation is on the line.
8. Use of leftovers
Using leftovers has been the cause of many outbreaks of food poisoning because of improper cooling and reheating (of “hot” leftovers). Leftovers that are intended to be served hot pass through the danger zone twice (during the initial cooling of the hot food and when reheating). Those leftovers intended to be served without reheating, or as an ingredient in other foods (e.g., sandwich filler), go through the danger zone during cooling and then, when being prepared and portioned, often stay in the danger zone for another long period. The time in the danger zone adds up unless the food is quickly cooled and then quickly reheated (if being served hot), or kept cold until serving (if not being served hot).
Contamination can also occur with leftover foods when they are stored in the cooler. Improperly stored leftovers can accidentally be contaminated by raw foods (e.g., blood dripping from a higher shelf).
To prevent problems:
- Reheat leftovers only once. Throw out any leftovers that have already been reheated once.
- Do not mix leftover foods with fresh foods.
- Be sure to follow the proper cooling and reheating procedures when handling leftovers. These are critical control points.
- Cool leftovers in uncovered containers separate from any raw foods. After they are cooled, cover them tightly.
9. Cross-contamination
You can expect certain foods to contain pathogens, especially raw meat, raw poultry, and raw seafood. Use extreme caution when you bring these foods into your kitchen. Cross-contamination happens when something that can cause illness (pathogens or chemicals) is accidentally put into a food where not previously found. This can include, for example, pathogens from raw meats getting into ready-to-eat foods like deli meats. It can also include nuts (which some people are very allergic to) getting into a food that does not normally have nuts (e.g., tomato sauce).
To prevent problems:
- Use separate cutting boards, separate cleaning cloths, knives/utensils, sinks, preparation areas, etc., for raw and for ready-to-eat foods. Otherwise, wash all of these items with detergent and sanitize them with bleach between use.
- Use separate storage areas for raw and ready-to-eat foods. Always store ready-to-eat foods on separate shelves and above raw foods. Store dry foods above wet foods.
- Prepare ready-to-eat foods at the beginning of the day before the raw foods are prepared.
- After handling raw foods, always wash your hands properly before doing anything else.
- Keep wiping or cleaning cloths in a container of fresh bleach solution (30 mL/1 oz. of bleach per 4 L/1 gal. of water) when not in use.
- Use clean utensils, not your hands, to handle cooked or ready-to-eat foods.
- If a customer indicates a food allergy, follow all the same steps to avoid cross contamination and use separate or freshly sanitized tools and utensils to prepare food for the individual with the allergy.
10. Inadequate cooking
Proper cooking is one of the best means of making sure your operation does not cause a food-poisoning outbreak. Proper cooking kills all pathogens (except spores) or at least reduces their numbers to a point where they cannot make people sick. Inadequate cooking is often done by accident: for example, cooking still-frozen poultry or meat; attempting to cook a stuffed bird using the same time and temperature as an unstuffed bird; using an inexperienced cook.
To prevent problems:
- Don’t rely on cooking times alone. Check the internal temperature of the food being cooked.
- For large cuts of meat or large batches of food, check the temperature in several spots.
- Be extra careful when cooking partially frozen foods. There can be cold spots in the food that are not properly cooked. The normal cooking time will have to be increased.
- When grilling or frying meat, cook until the juices run clear. Cooked fish until it flakes easily. Make thin, not thick, hamburgers.
Image descriptions
Figure 1 image description:
At 100°C (or 212°F), water boils. Above 74°C (or 165°F), bacteria die, although spores and toxins may survive. Food that is being cooked or reheated should hit 74°C (or 165°F). You can hold hot food for service at 60°C (or 140°F). Between 4°C and 60°C (or 40°F and 140°F) is the “Danger Zone.” Keep food out of this temperature range because bacteria will multiply rapidly. Between 0°C and 4°C (or 32°F and 40°F), most bacteria will survive but will not multiply quickly. Water freezes at 0°C (or 32°F). Between 0°C and −18°C (or 0°F and 32°F), most bacterial will survive but not grow. Frozen food is stored at −18°C (or 0°F).
Figure 2 image description:
- Improper cooling, 30%.
- Advance preparation, 15%.
- Infected person, 12%.
- Inadequate reheating, 10%.
- Improper hot holding, 8%.
- Contaminated raw food, 4%.
- Unsafe source, 3%.
- Use of leftovers, 2%.
- Cross-contamination, 2%.
- Inadequate cooking, 1%.
- All other causes, 3%.


12.1: Administering Oral Medications
By the end of this section, you will be able to:
- Explain the difference in various routes of oral medication
- Define various preparations of oral medications
- Demonstrate accurately the steps in medication administration
Medication administration routes refer to the way in which medications are given to the patient. The most common route of medication administration is the oral route (Ralston, 2018). Medications administered via the oral route may be supplied in a variety of forms. Depending on the drug and medication form, there are implications for practice that the nurse must be aware of and must follow. Following these implications are essential for nursing practice, because there are legal ramifications for not following the proper administration practices and techniques, including documenting the administration of medications. Within this section, we will explore aspects of proper administration for oral medications.
See the competency checklist for Administering Oral Medications. You can find the checklists on the Student resources tab of your book page on openstax.org.
Routes of Oral Medication
Administering medications via the oral route is simple and convenient. It is a widely acceptable route of administration that is the method by which most medications are administered in the home setting. Medications administered orally may begin in the mouth, enter the stomach, and usually end in the small intestine. While the oral route is the overarching umbrella, there are additional routes that fall under the oral umbrella, such as sublingual, buccal , and feeding tubes.
Oral
Medications ordered to be administered via the oral route ( per os , or PO) are to be taken by mouth. After being swallowed, the medication is most often absorbed in the small intestine. Absorption of oral medications may be affected by factors such as the presence of gastric acid, food intake, absorption through the small bowel, and metabolism by liver enzymes (also known as first-pass drug metabolism ) (Kim & De Jesus, 2023). Oral medications have a slow onset, typically about thirty to sixty minutes after administration.
Sublingual
Medications ordered to be administered via the sublingual route are placed under the tongue (Figure 12.2). These medications dissolve rapidly into the bloodstream for fast absorption and are not affected by first-pass drug metabolism, where the liver metabolizes or chemically alters the medication before it reaches the systemic circulation. Sublingual medications may be affected by eating, drinking, and smoking; therefore, they should not be swallowed, chewed, or taken with water. Due to the rapid absorption, medications administered via this route typically are used to treat emergencies, such as chest pain, allergies, or opioid dependence. Two medications commonly administered via the sublingual route are nitroglycerin (Nitrostat) and buprenorphine/naloxone (Suboxone). Suboxone, a combination medication used for long-term treatment of opioid dependence and opioid use disorder, is not to be confused with naloxone, an opioid antagonist used for the emergency treatment of opioid overdoses.
Buccal
Medications ordered to be administered via the buccal route are to be placed between the gum and the cheek (Figure 12.3). These medications dissolve rapidly into the bloodstream for fast absorption and are not affected by first-pass drug metabolism. Like sublingual medications, buccal medications may be affected by eating, drinking, and smoking; therefore, they should not be swallowed, chewed, or taken with water. Examples of medications that may be administered buccally include fentanyl (Sublimaze), naloxone ( Narcan ), and midazolam (Versed).
Feeding Tubes
Some oral medications may also be administered via a feeding tube, such as a nasogastric tube (NG tube), gastrostomy tube (G tube), or jejunostomy tube (J tube). Not all oral medications are intended to be administered via a feeding tube; therefore, careful consideration should be given to the compatibility of the medication to be administered via the feeding tube route. Medications administered via a feeding tube need to be supplied in a liquid form, if available, or crushed and diluted if supplied in a solid form. To ensure safe practice of medication administration , it is recommended that an interdisciplinary team work together to form agency protocols for the medications administered via feeding tubes. It is also recommended that medications intended to be administered via a feeding tube be specifically ordered as such. The ordered route should state to administer the medication via the NG tube, G tube, or J tube, rather than PO.
Preparations of Oral Medication
Oral medications may be supplied in a variety of forms, such as solids, liquids, and suspensions. Within each form, there are several different preparation types, each with their own administration considerations. The nurse must be familiar with the various preparations and the techniques associated with each preparation to ensure that safe medication administration practices are followed.
Solids
Solid preparations of oral medications include powders, tablets, capsules, caplets, gelcaps, and lozenges. A powder is made of fine particles created from grinding a solid. A tablet is comprised of compressed powder or granules. An enteric-coated tablet is covered in a substance that delays the medication from dissolving. Enteric-coated tablets often are marked with an EC at the end of the medication name to alert the nurse to the type of medication. A capsule is powder or granules contained in a gelatin shell. A time-released capsule or tablet contains granules that slowly release for prolonged action of the medication. Time-released capsules typically have the abbreviations CR (controlled release), SR (sustained release), or ER or XR (extended release). A caplet is a solid, compressed powder or granules that are sometimes coated to make it easier to swallow. A gelcap is a soft gelatin shell with a liquid drug inside. A lozenge is a medication in a candy base that is meant to dissolve in the mouth.
Solid medications usually come prepared in a blister pack or bottle (Figure 12.4). Blister packs typically come in single-use packaging, whereas bottles contain multiple doses of the medication (multidose packages). Medications that come prepared in a blister pack protect the pills from being handled until the medication is opened at the patient’s bedside. Medications that come prepared in a bottle require handling and the medication must be placed in a paper or graduated plastic cup or oral syringe in the medication preparatory area before taking it to the patient’s bedside.
Liquids
Liquid preparations of oral medications include syrups, elixirs, and emulsions. A syrup is a liquid form of a medication that contains added sugars and flavors. An elixir is a liquid form of a medication that contains added sugars, flavors, and alcohol. An emulsion is a solution that contains a medication, water, and oil mixture. Emulsions should not be administered to patients experiencing difficulty swallowing because of the risk of aspiration . When administering liquid medications, it is important to shake the medication well before measuring the dose.
Suspensions
A suspension requires undissolved drug particles to be mixed with a liquid agent before administration. It is important to shake the suspension well before administering the medication. Typically, liquid and suspension medications are prepared using an oral syringe, dosing cup, medication dropper, or medication spoon (Figure 12.5). Household spoons, such as flatware, are not recommended for measuring medications because they are not uniform in size.
Steps for Oral Medication Administration
When administering medications, patient safety is the top priority. Therefore, considerations must be given throughout the medication process to ensure practices are in place that promote safe medication administration . This includes confirming the medication “rights” when collecting, preparing, and administering medications.
Before administering oral medications, the nurse should assess for contraindications that would prohibit the patient from being able to receive the medication, such as dysphagia, NG tube with gastric suctioning, NPO (nothing passed orally) status, or the inability to sit upright. After determining that oral medications may be safely administered, the nurse should verify the medication administration record (MAR) against the prescribing provider’s orders. The nurse should then remove the medications from the medication cabinet, drawer, or automated dispensing cabinet, confirming the medication rights for each medication. The medications should then be prepared, confirming the rights for each medication a second time.
After the medications have been prepared, the nurse is then ready to administer the medications. After confirming the rights for each medication for a third time, the nurse should assist the patient into an upright position (Figure 12.6). If the patient is unable to be placed in the upright position, a side-lying position may be used; however, the nurse should use caution to ensure the patient’s ability to swallow in this position. When positioned, the nurse should offer the patient something to drink. Consideration should be given to ensure the liquid offered is not contraindicated with any of the medications the patient is taking, and that the oral intake is accounted for within the medication record. Ask the patient if they prefer to take all medications at once or if they prefer the medications to be placed in the cup one at a time. Remain with the patient to ensure all medications are swallowed before documenting the medication administration. Perform any required post-assessments (e.g., blood pressure checks or pain reassessments) and document the patient's response to the medication.
Disclaimer: Always follow the agency’s policy for medication administration.
Definition: Reduce the risk of harm to patients through effective, efficient, and competent performance.
Knowledge: The nurse will analyze basic safety principles, understand evidence-based practice standards, and reflect on unsafe nursing practices (such as workarounds and dangerous abbreviations).
Skill: Demonstrate effective strategies to reduce the risk of harm. The nurse will:
- Avoid distractions and minimize disruptions when administering medications.
- Perform hand hygiene before handling and administering medications.
- Prepare medications for one patient at a time.
- Transport medications carefully in your hands, not in your pockets.
- Listen to the patient and explore any concerns they may express.
- If difficulties in swallowing are noted, do not administer medications until the concern is discussed with the prescribing provider.
- If the patient is NPO, clarify with the prescribing provider whether oral medications should be administered.
- If the patient has a feeding tube, clarify the intended route of medication administration with the prescribing provider, and ensure the order correctly identifies the feeding tube route.
- Dispose of unused medication according to agency policy. Controlled substances must be wasted. The waste must be witnessed by another nurse and documented by both nurses.
Attitude: The nurse will accept their individual role in preventing errors by adhering to safe, evidence-based practice standards.
Special Techniques
Several special techniques may need to be applied when administering oral medications. Although most oral medications are swallowed, there may be special instructions for the patient, such as “swish and spit” or gargling the medication. Some medications (e.g., magic mouthwash formulated to prevent or treat mouth sores) are ordered for the patient to swish the medication around in the mouth to coat as much surface area in the mouth as possible and then spit it out without swallowing the medication. Other medications, such as lidocaine, may be ordered as a gargle. The medication is moved around in the mouth and throat and then spit out without swallowing any of the medication. Some medications, such as tetracycline, doxycycline, and chlorhexidine, are known to discolor or stain teeth. In these instances, the patient may be instructed to rinse their mouth or perform oral hygiene after swallowing the medication.
Sometimes a medication may need to be divided before being administered. Tablets that are scored (Figure 12.7) may be divided in half, thirds, or quarters, depending on how the tablet is scored. This technique may be used when the ordered dose is smaller than the supplied dose. For example, the prescribing provider may order enalapril maleate (Vasotec) 7.5 mg PO daily. The pharmacy supplies 5 mg tablets of enalapril maleate. After calculating the dose, the nurse determines that the patient should receive 1.5 tablets. Using the scored line, the nurse divides one tablet in half and disposes of the other half according to agency policy.
To properly divide the tablet, the nurse may use a pill splitter or break the tablet by hand (Figure 12.8). A pill splitter is preferred to ensure the most accurate splitting of the tablet. When using a pill splitter, align the scored marks on the tablet with the blade of the pill splitter and push down on the lid of the pill splitter. If a pill splitter is not available, tablets may be broken by hand by positioning the fingers on either side of the scored line and pressing down or by pressing down on the tablet on a solid surface. When breaking a tablet, it is important to ensure hand hygiene is performed and gloves are worn while handling the medication. Other forms of oral medications, such as capsules, caplets, and gelcaps are not scored; therefore, they cannot be divided.
There may also be times when a medication needs to be crushed. For instance, if the patient is having difficulty swallowing, the medication needs to be crushed into a powder that can be dissolved in a liquid or administered via a feeding tube. Most tablets may be crushed; however, other forms of oral medications, such as capsules, caplets, and gelcaps cannot be crushed. Tablets that are designed to be controlled release (e.g., extended-release tablets) or that are coated (e.g., enteric-coated tablet s) should never be crushed. Crushing medications that are not designed to be crushed may cause serious side effects, prevent the medication from working properly, or alter how the body processes the medication. Medications can be crushed using a pill crusher (Figure 12.9) and then mixed with applesauce, pudding, or another easily swallowed food or liquid. It is important to crush medications one pill at a time while at the patient’s bedside after ensuring the “rights” of medication administration .
Administering oral medications to children requires special considerations. For instance, precise medication dosing is required for pediatric patients. Furthermore, children may be reluctant or unable to swallow medications. These and other factors require attention to detail and patience on the nurse’s part.
Several factors should be kept in mind when administering oral medications to children. Sometimes, children are reluctant to take medications. In these instances, it may be helpful to mix the medication with a soft food (e.g., applesauce) when possible or have the child’s caregiver assist with administering the medication. Medications may need to be prescribed in a liquid or chewable form if the child is unable to swallow medications in a solid form. When administering liquid medications to a child, an oral syringe or medication dropper may be used to provide a precise measurement of the medication. Liquid medications should be squirted between the child’s gum and cheek to avoid aspiration. It is important for the nurse to be patient when administering medications to children and to try to address the child’s and caregiver’s fears.
Nursing Roles and Responsibilities
When administering medications, one of the key responsibilities of the nurse is to assess the patient. Assessment is required before administering medications, during administration, as well as after administration. As previously noted, the nurse must assess the patient’s current status, ability to swallow, and whether they are NPO before administering medications. Also, at times, vital signs should be assessed before administration. For example, heart rate and blood pressure should be assessed before administering cardiac medications. If the blood pressure or heart rate is low, then the medication may need to be held to prevent the vital signs from dropping even further. Laboratory results may also need to be reviewed. For example, if the patient’s potassium level is high, administering more potassium likely will increase the potassium level even higher and can lead to toxicity. In addition, an assessment is needed before administering PRN (pro re nata, or as needed) medications. For example, the nurse should assess pain prior to administering pain medications and assess sleep patterns prior to administering a sleep aid. Should the nurse’s clinical judgment warrant holding the medication, the prescribing provider must be notified.
During administration, the nurse should assess the patient’s safety. This assessment should include confirming the patient’s identity, checking allergies, reviewing the medication “rights,” assessing the patient’s ability to safely swallow medications, and identifying any sudden changes in the patient’s condition. Should the patient begin to show signs of difficulty swallowing (i.e., coughing, choking, gurgling), the nurse should not administer any additional medications until the patient is further assessed and can safely swallow.
Post-administration, the nurse should assess the patient’s response to medications. This assessment should include the patient’s tolerance to the medications, whether the intended response occurred, re-assessing indications for PRN medications, as well as monitoring for adverse reactions. The post-administration assessment is important and may be used for clinical decision-making to determine next steps in the patient’s care. For example, if the patient is still experiencing pain after receiving pain medications, perhaps a different medication may be warranted, or additional nonpharmacological strategies may be needed. If the patient experiences an adverse reaction, the nurse may anticipate the medication to be discontinued and new orders may be required.
Other roles of the nurse include educating the patient and reporting medication errors. It is important to educate patients and their caregivers on the medications being administered, potential side effects, and special precautions that must be taken. Educating the patient on the correct process of medication administration helps the patient know what to expect and how to identify any discrepancies in the process. Should any medication errors, or potential errors occur, it is important for the nurse to report these errors according to the agency policy. Reporting medication errors encourages transparency, which allows for proper follow-up and identification of root causes. This is necessary for process and practice improvements to be made.
Nurses are legally responsible for ensuring safe and accurate administration of medications and may be held liable for medication errors. The nurse is also legally responsible for delegated tasks. Some states may allow the nurse to delegate medication administration to unlicensed assistive personnel (UAP) (Carder & O’Keeffe, 2016). In these instances, the nurse is responsible for supervising the UAP throughout the medication administration process. Although some tasks may be delegated to the UAP, the nurse remains responsible for the assessment, planning, teaching, evaluation, and nursing judgment associated with the administration of medications.
Delegation Considerations
When delegating medication administration to the UAP, the nurse must ensure the five rights of delegation: right task, right circumstance, right person, right directions and communication, and right supervision and evaluation. In determining the right task, it is important for the nurse to ensure the UAP has received the appropriate training and has been deemed competent in the skill. In determining the right circumstance, the nurse should consider the patient’s circumstances before delegating the task. Instances in which the results are unpredictable, risks are involved, or medication administration challenges are predicted should not be delegated to the UAP. The right person involves delegating the right task for the right person. It is important for the nurse to be aware of which UAPs have been credentialed to administer medications and correctly identify the patient to receive the medication. In ensuring the right directions and communication, the nurse should provide clear instructions regarding the task that needs to be completed, when it should be completed, as well as any additional expectations associated with the task. The right supervision and evaluation requires the nurse to provide appropriate monitoring, evaluation, intervention, and feedback.


8.17: Video- Starbucks Delivers Community and Connection
What business is Starbucks really in?
“We wanted to build a third place between home and work,” says Starbucks’ CEO Howard Schultz, as he sits in one of his cafés, “at a time in America when people are hungry for human connection.”
Watch the following video to learn how, from the beginning, Starbucks has positioned itself to be much more than just a seller of gourmet coffee. It has built its entire brand experience around a core positioning that offers “a sense of community” as much as coffee.
You can view the transcript for “Starbucks the Brand” (opens in new window).
Contributors and Attributions
- Starbucks Delivers Community and Connection. Provided by : Lumen Learning. License : CC BY: Attribution
- Starbucks the Brand. Provided by : BBC. Located at : https://youtu.be/tnHuGN3umTA . License : CC BY-NC-ND: Attribution-NonCommercial-NoDerivatives


5: The Greek World from Bronze Age to Roman Conquest
This chapter’s title refers to the Greek World, rather than Greece. While Greece is a unified country today, the territory of the present-day country was not unified under one rule until the rise of the Macedonians in the fourth century BCE. Instead, the basic unit of organization in the period covered in this chapter was the polis , an independent city-state, which consisted of a walled city that controlled and protected the farmland around it. Historians estimate that close to 1,500 of these city-states dotted the ancient Greek landscape.
-
- 5.5: Geography and Topography
- Each polis possessed its own form of government, law-code, army, cults of patron gods, and overall culture that set it apart from the other city-states. While the two most famous poleis, Athens and Sparta, controlled vast territories of farmland, most city-states were small, with a population of just a few thousand citizens. Furthermore, the Greek world in antiquity encompassed much more than present-day Greece, extending as far as Italy and the territories of modern-day Turkey and Ukraine.
-
- 5.7: Methodology- Sources and Problem
- Modern scholars of ancient history are notoriously obsessed with evaluating their primary sources critically, and with good reason. Studying Greek history, especially in its earliest periods, is like putting together a puzzle, most of whose pieces are missing, and some pieces from another puzzle have also been added in for good measure. Greek history requires careful consideration of a wide range of sources, which fall into two broad categories: literary sources and material culture.
-
- 5.8: From Mythology to History
- Mythology refers to stories that are clearly false, of long-forgotten gods and heroes and their miraculous feats. History, on the other hand, refers to actual events that involved real people. And yet, the idea that the two are opposites would have seemed baffling to a typical resident of the ancient Mediterranean world. Rather, gods and myths were part of the everyday life, and historical events could become subsumed by myths just as easily as myths could become a part of history.
-
- 5.9: Archaic Greece
- The Archaic period was a time of growing contacts and connections between different parts of mainland Greece. Furthermore, it was a time of expansion, as the establishment of overseas colonies and cities brought the Greeks to Italy and Sicily in the West, and Asia Minor and the Black Sea littoral in the East. Furthermore, while Greeks in the Archaic period saw themselves as citizens of individual city-states, this period also witnessed the rise of a Pan-Hellenic identity.
-
- 5.10: The Classical Period
- The story of the Greeks in the Classical Period is best described as the strife for leadership of the Greek world. First, Athens and Sparta spent much of the fifth century BCE battling each other for control of the Greek world. Then, once both were weakened, other states began attempting to fill the power vacuum. Ultimately, the Classical Period will end with the Greek world under the control of a power that was virtually unknown to the Greeks at the beginning of the fifth century BCE: Macedon.
-
- 5.11: Hellenistic Period
- Historians today consider the death of Alexander to be the end point of the Classical Period and the beginning of the Hellenistic Period. That moment, for historians, also marks the end of the polis as the main unit of organization in the Greek world. While city-states continued to exist, the main unit of organization from that point on was the great Hellenistic kingdoms. These kingdoms, encompassing much greater territory than the Greek world had before Alexander.
-
- 5.12: Conclusion
- In some respects, this spread of the Greeks and their civilization ultimately changed what it meant to be Greek–or, rather, it created a more universal Greek identity, which largely replaced the polis-specific view of citizenship and identity that existed before Philip’s conquest of Greece. And yet, certain cultural constants persisted."
Thumbnail: Roman bronze reduction of Myron's Discobolus, 2nd century AD (Glyptothek, Munich). (CC BY 2.5; MatthiasKabel).


20.13: Stroop Interference
-
- Last updated
- Save as PDF
Learning Objectives
- Strrop Interference demonstration
Research conducted by
Statistics Class
Case study prepared by
David Lane
Overview
Naming the ink color of color words can be difficult. For example, if asked to name the color of the word " blue " is difficult because the answer (red) conflicts with the word "blue." This interference is called "Stroop Interference" after the researcher who first discovered the phenomenon.
This case study is a classroom demonstration. Students in an introductory statistics class were each given three tasks. In the "words" task, students read the names of \(60\) color words written in black ink; in the "color" task, students named the colors of \(60\) rectangles; in the "interference" task, students named the ink color of \(60\) conflicting color words. The times to read the stimuli were recorded. There were \(31\) female and \(16\) male students.
Questions to Answer
Is naming conflicting color names faster or slower than naming color rectangles? Which is faster, naming color rectangles or reading color names? Are there gender differences?
Design Issues
This was not a well-controlled experiment since it was just a classroom demonstration. The order in which the students performed the tasks may not have been counterbalanced or randomized.
Descriptions of Variables
|
Variable
|
Description
|
| Gender | 1 for female, 2 for male |
| Words | Time in seconds to read 60 color words |
| Colors | Time in seconds to name 60 color rectangles |
| Interfer | Time in seconds to name colors of conflicting words |
Data Files
Stroop.xls
Links
Full text of the above reference.
References
- Stroop, J.R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 28, 643-662.


3.2: Articulation
- An introduction to the most common musical articulation markings.
What is Articulation?
The word articulation generally refers to how the pieces of something are joined together; for example, how bones are connected to make a skeleton or syllables are connected to make a word. Articulation depends on what is happening at the beginning and end of each segment, as well as in between the segments.
In music, the segments are the individual notes of a line in the music. This could be the melodic line, the bass line, or a part of the harmony. The line might be performed by any musician or group of musicians: a singer, for example, or a bassoonist, a violin section, or a trumpet and saxophone together. In any case, it is a string of notes that follow one after the other and that belong together in the music.The articulation is what happens in between the notes. The attack - the beginning of a note - and the amount of space in between the notes are particularly important.
Performing Articulations
Descriptions of how each articulation is done cannot be given here, because they depend too much on the particular instrument that is making the music. In other words, the technique that a violin player uses to slur notes will be completely different from the technique used by a trumpet player, and a pianist and a vocalist will do different things to make a melody sound legato. In fact, the violinist will have some articulations available (such as pizzicato, or "plucked") that a trumpet player will never see.
So if you are wondering how to play slurs on your guitar or staccato on your clarinet, ask your music teacher or director. What you will find here is a short list of the most common articulations: their names, what they look like when notated, and a vague description of how they sound. The descriptions have to be vague, because articulation, besides depending on the instrument, also depends on the style of the music. Exactly how much space there should be between staccato eighth notes, for example, depends on tempo as well as on whether you're playing Rossini or Sousa.  (For more audio examples of violin articulations, please see Common Violin Terminology .)
Common Articulations
Staccato notes are short, with plenty of space between them. Please note that this doesn't mean that the tempo or rhythm goes any faster. The tempo and rhythm are not affected by articulations; the staccato notes sound shorter than written only because of the extra space between them.
Staccato
Legato is the opposite of staccato. The notes are very connected; there is no space between the notes at all. There is, however, still some sort of articulation that causes a slight but definite break between the notes (for example, the violin player's bow changes direction, the guitar player plucks the string again, or the wind player uses the tongue to interrupt the stream of air).
Legato
Accents - An accent requires that a note stand out more than the unaccented notes around it. Accents are usually performed by making the accented note, or the beginning of the accented note, louder than the rest of the music. Although this is mostly a quick change in dynamics, it usually affects the articulation of the note, too. The extra loudness of the note often requires a stronger, more definite attack at the beginning of the accented note, and it is emphasized by putting some space before and after the accented notes. The effect of a lot of accented notes in a row may sound marcato.
Accents
A slur is marked by a curved line joining any number of notes. When notes are slurred, only the first note under each slur marking has a definite articulation at the beginning. The rest of the notes are so seamlessly connected that there is no break between the notes. A good example of slurring occurs when a vocalist sings more than one note on the same syllable of text.
Slurs
A tie looks like a slur, but it is between two notes that are the same pitch. A tie is not really an articulation marking. It is included here because it looks like one, which can cause confusion for beginners. When notes are tied together, they are played as if they are one single note that is the length of all the notes that are tied together. (Please see Dots, Ties, and Borrowed Divisions.)
Slurs vs. Ties
A portamento is a smooth glide between the two notes, including all the pitches in between. For some instruments, like violin and trombone, this includes even the pitches in between the written notes. For other instruments, such as guitar, it means sliding through all of the possible notes between the two written pitches.
Portamento
Although unusual in traditional common notation, a type of portamento that includes only one written pitch can be found in some styles of music, notably jazz, blues, and rock. As the notation suggests, the proper performance of scoops and fall-offs requires that the portamento begins (in scoops) or ends (in fall-offs) with the slide itself, rather than with a specific note.
Scoops and Fall-offs
Some articulations may be some combination of staccato, legato, and accent. Marcato, for example means "marked" in the sense of "stressed" or "noticeable". Notes marked marcato have enough of an accent and/or enough space between them to make each note seem stressed or set apart. They are usually longer than staccato but shorter than legato. Other notes may be marked with a combination of articulation symbols, for example legato with accents. As always, the best way to perform such notes depends on the instrument and the style of the music.
Some Possible Combination Markings
Plenty of music has no articulation marks at all, or marks on only a few notes. Often, such music calls for notes that are a little more separate or defined than legato, but still nowhere as short as staccato. Mostly, though, it is up to the performer to know what is considered proper for a particular piece. For example, most ballads are sung legato, and most marches are played fairly staccato or marcato, whether they are marked that way or not. Furthermore, singing or playing a phrase with musicianship often requires knowing which notes of the phrase should be legato, which should be more separate, where to add a little portamento, and so on. This does not mean the best players consciously decide how to play each note. Good articulation comes naturally to the musician who has mastered the instrument and the style of the music.


42.1: Innate Immune Response - Innate Immune Response
- Explain the purpose of the immune system
The environment surrounding all of us consists of numerous pathogens: agents (usually microorganisms) that cause disease(s) in their hosts. A host is the organism that is invaded and often harmed by a pathogen. Pathogens, which include bacteria, protists, fungi, and other infectious organisms, can be found in food and water, on surfaces, and in the air. Concern over pathogens is one of the main reasons that we wash our hands after going to the bathroom or touching raw meat.
Mammalian immune systems evolved for protection from such pathogens. They are composed of an extremely-diverse array of specialized cells and soluble molecules that coordinate a rapid, flexible defense system capable of providing protection from a majority of these disease agents. Central to this goal, the immune system must be capable of recognizing “self” from “other” so that when it destroys cells, it destroys pathogen cells and not host cells.
The immune response that defends against pathogens can be classified as either innate or active. The innate immune response is present in its final state from birth and attempts to defend against all pathogens. Conversely, the adaptive immune response stores information about past infections and mounts pathogen-specific defenses. It expands over time, gaining more information about past targets so that it can respond quickly to future pathogens. The adaptive immune response functions throughout the body to combat specific pathogens that it has encountered before (a process known as reactivation). However, we are born with only innate immunity, developing our adaptive immune response after birth.
Components of both immune systems constantly search the body for signs of pathogens. When pathogens are found, immune factors are mobilized to the site of an infection. The immune factors identify the nature of the pathogen, strengthen the corresponding cells and molecules to combat it efficiently, and then halt the immune response after the infection is cleared to avoid unnecessary host cell damage. Features of the immune system (e.g., pathogen identification, specific response, amplification, retreat, and remembrance) are essential for survival against pathogens.
Key Points
- The mammalian immune system has evolved an extremely-diverse array of specialized cells and soluble molecules that allow it to defend against a variety of pathogens, including bacteria, protists, fungi, and other infectious organisms.
- The innate immune response serves as a general defense against all pathogens, but has no capacity to adapt or learn when new pathogens attack.
- The adaptive immune response has a “memory” about previously encountered pathogens and is able to mount pathogen-specific defenses based on this memory.
Key Terms
- pathogen : any organism or substance, especially a microorganism, capable of causing disease, such as bacteria, viruses, protozoa, or fungi
- immune system : the system that differentiates self from non-self and protects the body from foreign substances and pathogenic organisms by producing an immune response


1.5.2: Relative Strengths of Acids and Bases
Learning Objectives
- Assess the relative strengths of acids and bases according to their ionization constants
We can rank the strengths of acids by the extent to which they ionize in aqueous solution. The reaction of an acid with water is given by the general expression:
\[\ce{HA}(aq)+\ce{H2O}(l)⇌\ce{H3O+}(aq)+\ce{A-}(aq)\]
Water is the base that reacts with the acid \(\ce{HA}\), \(\ce{A^{−}}\) is the conjugate base of the acid \(\ce{HA}\), and the hydronium ion is the conjugate acid of water. A strong acid yields 100% (or very nearly so) of \(\ce{H3O+}\) and \(\ce{A^{−}}\) when the acid ionizes in water; Figure \(\PageIndex{1}\) lists several strong acids. A weak acid gives small amounts of \(\ce{H3O+}\) and \(\ce{A^{−}}\).
| Six Strong Acids | Six Strong Bases | ||
|---|---|---|---|
| \(\ce{HClO4}\) | perchloric acid | \(\ce{LiOH}\) | lithium hydroxide |
| \(\ce{HCl}\) | hydrochloric acid | \(\ce{NaOH}\) | sodium hydroxide |
| \(\ce{HBr}\) | hydrobromic acid | \(\ce{KOH}\) | potassium hydroxide |
| \(\ce{HI}\) | hydroiodic acid | \(\ce{Ca(OH)2}\) | calcium hydroxide |
| \(\ce{HNO3}\) | nitric acid | \(\ce{Sr(OH)2}\) | strontium hydroxide |
| \(\ce{H2SO4}\) | sulfuric acid | \(\ce{Ba(OH)2}\) | barium hydroxide |
The relative strengths of acids may be determined by measuring their equilibrium constants in aqueous solutions. In solutions of the same concentration, stronger acids ionize to a greater extent, and so yield higher concentrations of hydronium ions than do weaker acids.
We can rank the strengths of bases by their tendency to form hydroxide ions in aqueous solution. The reaction of a base with water is given by:
\[\ce{B}(aq)+\ce{H2O}(l)⇌\ce{HB+}(aq)+\ce{OH-}(aq)\]
Water is the acid that reacts with the base, \(\ce{HB^{+}}\) is the conjugate acid of the base \(\ce{B}\), and the hydroxide ion is the conjugate base of water. A strong base yields 100% (or very nearly so) of OH − and HB + when it reacts with water; Figure \(\PageIndex{1}\) lists several strong bases. A weak base yields a small proportion of hydroxide ions. Soluble ionic hydroxides such as NaOH are considered strong bases because they dissociate completely when dissolved in water.
The Ionization of Weak Acids and Weak Bases
Many acids and bases are weak; that is, they do not ionize fully in aqueous solution. A solution of a weak acid in water is a mixture of the nonionized acid, hydronium ion, and the conjugate base of the acid, with the nonionized acid present in the greatest concentration. Thus, a weak acid increases the hydronium ion concentration in an aqueous solution (but not as much as the same amount of a strong acid).
Acetic acid (\(\ce{CH3CO2H}\)) is a weak acid. When we add acetic acid to water, it ionizes to a small extent according to the equation:
\[\ce{CH3CO2H}(aq)+\ce{H2O}(l)⇌\ce{H3O+}(aq)+\ce{CH3CO2-}(aq)\]
giving an equilibrium mixture with most of the acid present in the nonionized (molecular) form. This equilibrium, like other equilibria, is dynamic; acetic acid molecules donate hydrogen ions to water molecules and form hydronium ions and acetate ions at the same rate that hydronium ions donate hydrogen ions to acetate ions to reform acetic acid molecules and water molecules. We can tell by measuring the pH of an aqueous solution of known concentration that only a fraction of the weak acid is ionized at any moment (Figure \(\PageIndex{4}\)). The remaining weak acid is present in the nonionized form.
At equilibrium, a solution of a weak base in water is a mixture of the nonionized base, the conjugate acid of the weak base, and hydroxide ion with the nonionized base present in the greatest concentration. Thus, a weak base increases the hydroxide ion concentration in an aqueous solution (but not as much as the same amount of a strong base).
For example, a solution of the weak base trimethylamine, (CH 3 ) 3 N, in water reacts according to the equation:
\[\ce{(CH3)3N}(aq)+\ce{H2O}(l)⇌\ce{(CH3)3NH+}(aq)+\ce{OH-}(aq)\]
This gives an equilibrium mixture with most of the base present as the nonionized amine. This equilibrium is analogous to that described for weak acids.
We can confirm by measuring the pH of an aqueous solution of a weak base of known concentration that only a fraction of the base reacts with water (Figure 14.4.5). The remaining weak base is present as the unreacted form.
Example \(\PageIndex{6}\): Formic Acid in Ant stings
Formic acid, HCO 2 H, is the irritant that causes the body’s reaction to ant stings.
Summary
The strengths of acids and bases in aqueous solutions can be determined by their acid or base ionization constants. Strong acids are completely ionized in aqueous solution because their conjugate bases are weaker bases than water. Weak acids are only partially ionized because their conjugate bases are strong enough to compete successfully with water for possession of protons. Strong bases react with water to quantitatively form hydroxide ions. Weak bases give only small amounts of hydroxide ion.
Glossary
- percent ionization
- ratio of the concentration of the ionized acid to the initial acid concentration, times 100
Contributors and Attributions
-
Paul Flowers (University of North Carolina - Pembroke), Klaus Theopold (University of Delaware) and Richard Langley (Stephen F. Austin State University) with contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at<EMAIL_ADDRESS>).


41.1: Got Data?
Lesson
Let's explore different kinds of data.
Exercise \(\PageIndex{1}\): Dots of Data
Here is a dot plot for a data set.
-
Determine if each of the following would be an appropriate label to represent the data in the dot plot? Be prepared to explain your reasoning.
- Number of children per class.
- Distance between home and school, in miles.
- Hours spent watching TV each day.
- Weight of elephants, in pounds.
- Points received on a homework assignment.
-
Think of another label that can be used with the dot plot.
- Write it below the scale of the dot plot. Be sure to include the unit of measurement.
- In your scenario, what does one dot represent?
- In your scenario, what would a data point of 0 mean? What would a data point of \(3\frac{1}{4}\) mean?
Exercise \(\PageIndex{2}\): Surveying the Class
Here are some survey questions. Your teacher will explain which questions can be used to learn more about the students in your class and how the responses will be collected. The data that your class collects will be used in upcoming activities.
- How long does it usually take you to travel to school? Answer to the nearest minute.
-
How do you travel to school on most days? Choose one.
- Public transport
- Other
- Walk
- Bike
- Scooter or skateboard
- Car
- School bus
- How tall are you without your shoes on? Answer to the nearest centimeter.
- What is the length of your right foot without your shoe on? Answer to the nearest centimeter.
- What is your arm span? Stretch your arms open, and measure the distance from the tip of your right hand’s middle finger to the tip of your left hand’s middle finger, across your back. Answer to the nearest centimeter.
-
How important are the following issues to you? Rate each on a scale from 0 (not important) to 10 (very important).
- Reducing pollution
- Recycling
- Conserving water
- Do you have any siblings? _____ Yes _____ No
- How many hours of sleep per night do you usually get when you have school the next day? Answer to the nearest half hour.
- How many hours of sleep per night do you usually get when you do not have school the next day? Answer to the nearest half hour.
-
Other than traveling from school, what do you do right after school on most days?
- Have a snack
- Do homework
- Read a book
- Talk on the phone
- Practice a sport
- Do chores
- Use the computer
- Participate in an extracurricular activity
-
If you could meet one of these celebrities, who would you choose?
- A city or state leader
- A champion athlete
- A movie star
- A musical artist
- A best-selling author
-
Estimate how much time per week you usually spend on each of these activities. Answer to the nearest quarter of an hour.
- Playing sports or doing outdoor activities
- Using a screen for fun (watching TV, playing computer games, etc.)
- Doing homework
- Reading
Exercise \(\PageIndex{3}\): Numerical and Categorical Data
The list of survey questions in the activity earlier can help you complete these exercises.
-
The first survey question about travel
time
produces
numerical data
. Identify two other questions that produce numerical data. For each, describe what was measured and its unit of measurement.
-
Question #: ______
What was measured:
Unit of measurement: -
Question #: ______
What was measured:
Unit of measurement:
-
Question #: ______
-
The second survey question about travel
method
produces
categorical data
. Identify two other questions that produce categorical data. For each, describe what characteristic or feature was being studied.
-
Question #: ______
Characteristic being studied: -
Question #: ______
Characteristic being studied:
-
Question #: ______
-
Think about the responses to these survey questions. Do they produce numerical or categorical data? Be prepared to explain how you know.
- How many pets do you have?
- How many years have you lived in this state?
- What is your favorite band?
- What kind of music do you like best?
- What is the area code of your school’s phone number?
- Where were you born?
- How much does your backpack weigh?
- Name two characteristics you could investigate to learn more about your classmates. Make sure one would give categorical data and the other would give numerical data.
Are you ready for more?
Priya and Han collected data on the birth months of students in their class. Here are the lists of their records for the same group of students.
This list shows Priya’s records.
\(\begin{array}{lllllllllllllll}{\text{Jan}}&{\text{Apr}}&{\text{Jan}}&{\text{Feb}}&{\text{Oct}}&{\text{May}}&{\text{June}}&{\text{July}}&{\text{Aug}}&{\text{Aug}}&{\text{Sep}}&{\text{Jan}}&{\text{Feb}}&{\text{Mar}}&{\text{Apr}}\\{\text{Nov}}&{\text{Nov}}&{\text{Dec}}&{\text{Feb}}&{\text{Mar}}&{}&{}&{}&{}&{}&{}&{}&{}&{}&{}\end{array}\)
This list shows Han’s records.
\(1\quad 4\quad\quad 1\quad 2\quad 10\quad 5\quad 6\quad 7\quad 8\quad 8\quad 9\quad 1\quad 2\quad 3\quad 4\quad 11\quad 11\quad 12\quad 2\quad 3\)
- How are their records alike? How are they different?
- What kind of data—categorical or numerical—do you think the variable “birth month” produces? Explain how you know.
Summary
The table contains data about 10 dogs.
| dog name | weight (kg) | breed |
|---|---|---|
| Duke | \(36\) | German shepherd |
| Coco | \(6\) | pug |
| Pierre | \(7\) | pug |
| Ginger | \(35\) | German shepherd |
| Lucky | \(10\) | beagle |
| Daisy | \(10\) | beagle |
| Buster | \(35\) | German shepherd |
| Pepper | \(7\) | pug |
| Rocky | \(7\) | beagle |
| Lady | \(32\) | German shepherd |
- The weights of the dogs are an example of numerical data , which is data that are numbers, quantities, or measurements. The weights of the dogs are measurements in kilograms.
- The dog breeds are an example of categorical data , which is data containing values that can be sorted into categories. In this case, there are three categories for dog breeds: pug, beagle, and German shepherd.
Some data with numbers are categorical because the numbers are not quantities or measurements. For example, telephone area codes are categorical data, because the numbers are labels rather than quantities or measurements.
Numerical data can be represented with a dot plot (sometimes called a line plot). Here is a dot plot that shows the weights of the dogs.
We can collect and study both kinds of data by doing surveys or taking measurements. When we do, it is important to think about what feature we are studying (for example, breeds of dogs or weights of dogs) and what units of measurement are used.
Glossary Entries
Definition: Categorical Data
A set of categorical data has values that are words instead of numbers.
For example, Han asks 5 friends to name their favorite color. Their answers are: blue, blue, green, blue, orange.
Definition: Dot Plot
A dot plot is a way to represent data on a number line. Each time a value appears in the data set, we put another dot above that number on the number line.
For example, in this dot plot there are three dots above the 9. This means that three different plants had a height of 9 cm.
Definition: Numerical Data
A set of numerical data has values that are numbers.
For example, Han lists the ages of people in his family: 7, 10, 12, 36, 40, 67.
Practice
Exercise \(\PageIndex{4}\)
Tyler asked 10 students at his school how much time in minutes it takes them to get from home to school. Determine if each of these dot plots could represent the data Tyler collected. Explain your reasoning for each dot plot.
Exercise \(\PageIndex{5}\)
Here is a list of questions. For each question, decide if the responses will produce numerical data or categorical data and give two possible responses.
- What is your favorite breakfast food?
- How did you get to school this morning?
- How many different teachers do you have?
- What is the last thing you ate or drank?
- How many minutes did it take you to get ready this morning—from waking up to leaving for school?
Exercise \(\PageIndex{6}\)
- Write two questions that you could ask the students in your class that would result in categorical data. For each question, explain how you know that responses to it would produce categorical data.
- Write two questions that you could ask the students in your class that would result in numerical data. For each question, explain how you know that responses to it would produce numerical data.
Exercise \(\PageIndex{7}\)
Triangle \(DEF\) has vertices \(D=(-4,-4), E=(-2,-4),\) and \(F=(-3,-1)\).
- Plot the triangle in the coordinate plane and label the vertices.
- Name the coordinates of 3 points that are inside the triangle.
- What is the area of the triangle? Show your reasoning.
(From Unit 7.3.5)