Jack wants to test if runners on his cross-country team improve with his new training regimen. He takes their times at the beginning of the season and again at the end of the season.
-Runners in Jack's study improving their times due to running generally and not necessarily due to the new regimen is an example of which of the following threats?
A) Selection
B) Maturation
C) History
D) Instrumentation

Question

Quizplus · Accepted Answer

Maturation refers to the natural changes that occur in the participants over time which could affect the results of the study. In this case, the runners could improve their times naturally without the new training regimen. Therefore, the improvement could be due to maturation rather than the new regimen. Selection refers to biased sampling, history refers to external events that could affect the results, and instrumentation refers to changes in the measuring instrument that could affect the results.

Jack Wants to Test If Runners on His Cross-Country Team