Question

Stronger players A football coach hears that a new exercise program will increase upper-body strength better than lifting weights. He is eager to test this new program in the off-season with the players on his high school team. The coach decides to let his players choose which of the two treatments they will undergo for$3$weeks—exercise or weight lifting. He will use the number of push-ups a player can do at the end of the experiment as the response variable. Which principle of experimental design does the coach’s plan violate? Explain how this violation could lead to confounding.

Short answer

The principle of random assignment is violated, and this could lead to confounding because the players can have the same characteristics and it will affect the results.

Step-by-step solution

Given Information

We are given that the coach let the players decide whether they had to do weight lifting or exercise, and at last he will select by the push-ups, and we have to find out which principle of experiment is violated and how it could lead to confounding.

Explanation

There are three principles of experimental design: comparison, random assignment, and control and replication.

From these, comparison is satisfied because weight lifting and exercise are compared and control and replication are also satisfied because weight lifting is a control treatment.

However, random assignment is not satisfied because the coach lets the players decide the treatment and treatment is not given to them randomly. This could lead to confounding because the players' choosing weight lifting can be similar and that can affect the results.