Question

A football coach gives half his players a protein bar to eat before each game; the other players do not receive the protein bar. After a month of games, he analyzes their playing stats. He concludes the protein bar helped improve their performance on the field. How can the coach test the means to be sure the results are not likely to happen by chance?

A.He can rerandomize the results by separating the two groups randomly, then calculate the means and the difference of the means.
B.He can pick players at random and analyze their playing stats without calculating means.
C.He can analyze the two groups by calculating the means and the difference of the means.
D.He can pick the players he wants to analyze based on the best stats.

Answer 1

It's c. the only way he can compare both is by calculating both groups' mean and comparing it. Randomizing wont work because it is mixing both protein bar users and non-protein bar players.