Jack wants to test whether runners on his cross-country team improve with his new training regimen. He measures their run 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?

Question

Quizplus · Accepted Answer

Maturation refers to changes that occur within the participants over time, such as physical or developmental changes, that may affect the outcome of the study. In this case, runners may improve their times simply due to natural improvements in their physical fitness over the course of the season, rather than due to the new training regimen. Selection refers to the bias that may occur in which participants are included or excluded from the study. History refers to external events or factors that may influence the outcome of the study. Instrumentation refers to changes in the measurement instrument or methods used to collect data that may affect the outcome of the study.

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