Question

Elias conducted an experiment about the effects of exercise on the heart rate of teenagers. Before morning basketball practice, he asked the members of his high school team to be his subjects. He measured each of their heart rates before and after a set of exercises. Which change would most reduce the bias of his experimental design?

Answer 1

What would most likely reduce the bias present in Elias' experimental design would be to not ask just the members of his high school team to be the subjects because they represent a very specific group of people. It would be much better to use a random group of people and have them do the same thing.