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?
Speeds of 65 mph are permitted only on controlled access highways, such as the Northway (I87) or Thruway, that are specifically posted for the 65 mph speed limit. However, even these highways are not posted for 65 mph over their entire lengths.