Question

A track and field coach wants to analyze the effect of sports drinks on the performance of his athletes. He decides to test three brands: Powerade, Gatorade and Vitaminwater. He will have each of the athletes complete a 400 meter run and record their times.

Which of the following represents a confounding variable? Mark all that apply.

A. He decides to give all male athletes Gatorade and the female athletes either Powerade or Vitaminwater.
B. He allows each athlete to choose their favorite drink from a cooler.
C. He has some of the athletes drink the sports drink two hours before running,others one hour before running, and the rest 30 minutes before running.
D. He has some of the athletes drink Gatorade two hours before running, others drink Powerade one hour before running, and the rest Vitaminwater half an hour before running.

Answer 1

Explanation:

A confounding variable is a variable that affects the independent and dependent variables and may cause a false association between them. Therefore, in this case:

A. Giving males a different sports drink than females could be a confounding variable since gender may affect their performance.

C. The timing of the sports drink consumption could also be a confounding variable since it may affect the athlete's performance.

D. Giving different brands of sports drinks to the athletes can be a confounding variable since the different formulas in the sports drinks might affect the results.

Therefore, options A, C, and D represent confounding variables. Option B does not represent a confounding variable since allowing athletes to choose their preferred drink from a cooler is a valid way to ensure that each athlete is comfortable with their sports drink.