Dr McGlynn Is Conducting a Study on the Influence of Exercise

Multiple Choice

Dr. McGlynn is conducting a study on the influence of exercise on reaction time. He allows subjects to exercise strenuously for either 0, 10, or 20 minutes. Next, subjects are seated at a table containing a red push button and a yellow light. Each subject is asked to push the button as soon as he or she sees the light flash. Dr. McGlynn measures the time it takes each subject to push the button after the light is lit. How many experimental groups does this study involve?

A) 1
B) 2
C) 3
D) 4
E) No groups are involved.