Corey is interested in the effects of movies on road rage. He assigns one group of individuals to watch a comedy prior to a test drive and a second group watches a violent action movie prior to a test drive. During the test drive, Corey measures how much each person swears and yells at other cars.

The independent variable in Corey's experiment is:

An individual's normal driving behavior

The control group

How much the individual swears during the test drive

Type of movie watched