A Researcher Is Interested in the Effect of Exercise on Stamina

Multiple Choice

A researcher is interested in the effect of exercise on stamina in elderly patients. The patients are randomly assigned to be in a high-exercise or low-exercise training program for eight weeks. At the end of the program, their stamina is measured by seeing how long they can walk comfortably on a treadmill. In this study, the dependent variable is

A) the number of minutes on the treadmill.
B) the exercise program (high versus low) .
C) the number of elderly patients.
D) the eight-week duration of the exercise program.