An Alternative Definition for IQR. In some texts, the interquartile range is defined differently. It is defined as the difference between the largest and smallest values in the middle 50% of a set of data. To compute an interquartile range using this definition, first remove observations from the lower quartile.
A hard drive is a device used to store data in a semipermanent state on your computer. Computer memory is a series of small packets of data called bits. Each bit is a 1 or a 0, and each bit is stored as a small magnetic charge on the hard drive. A read/write head moves over the hard drive to retrieve or rewrite the bits as needed.
They allow the user to input specific types of information to be stored in the computer's memory. Many drives are input-only, meaning they can only read information. Other drives, such as CD and DVD writers, can output information to physical media. The most common drive is a hard disk drive (HDD). This drive is usually located inside the computer and is accessed directly through its operating system. The HDD serves as a computer's main source of storage. Media files, documents, games and entire operating systems can be called up at will from the HDD.