An experiment was conducted to determine the effects of exercise on stress. Forty college students were given a questionnaire to measure their current level of stress. Next, they were randomly assigned to two groups: a Control Group (N = 20) and a Treatment Group (N = 20). Then for 4 weeks, the Treatment Group met 5 times per week for an exercise class. The Control Group was instructed to listen to music for the same amount of time, 5 times each week. Finally, each subject was given the stress questionnaire again.

(a) What type of experimental design is this? Explain.

(b) What is the independent variable? How many levels of the IV are there?

(c) What is the dependent variable?

(d) What kind of variable (quantitative or qualitative) is the independent variable?

(e) What kind of variable (quantitative or qualitative) is the dependent variable?