Suppose that a team of doctors is planning a study to test the effects of pain-relieving medications and exercise on arthritis. The two dosages of pain-relieving medications are 500 mg and 0 mg (placebo). The three levels of exercise are 20 minutes of exercise five days a week, 20 minutes of exercise three days a week, and 0 minutes of exercise. A random sample of 150 adults with arthritis were selected at random, and 25 were assigned to each of the six combinations of pain-relieving medications and exercise.
Which of the following statements about this experiment are true?
a. The treatments are the six combinations of the three levels of exercise and the two dosages of anti anxiety medication.
b. The factors are the six combinations of the three levels of exercise and the two dosages of anti-anxiety medication.
c. The treatments are exercise and anti-anxiety medication.
d. The subjects of the experiment are the different means of treating anxiety.
e. The factors are exercise and anti-anxiety medication.
f. The subjects of the experiment are the 240 adults who suffer from anxiety.