Types of Variables. It is very important when designing a research study that the researcher fully understands the variables in the study in order for the results to be valid and have meaning. A variable is something in the study that can be changed such as a characteristic or a value. The most common types of variables, especially when study cause and effect relationships, are the independent and dependent variables. The independent variable is the one that can be controlled or manipulated.
What's the maximum speed you can travel on a freeway with a 65 mph speed limit and be absolutely guaranteed not to get a speeding ticket? 65 mph. That's why it's called a speed limit. Any faster and you will be violating the statute which sets the limit. Now... is it likely you'll get stopped and cited at 66 mph?
Speed limits are for the most part ignored in and around the city, even though on I-4 the speed limit is only 50 mph (80 km/h) in the downtown area and ranges between 55 and 65 mph (90-105 km/h) near the attractions, it is not uncommon to be tailgated if you travel less than 80 mph (129 km/h) in the left lane.