Dr. Feliciano is conducting a study of sleep on children's activity level that takes place over several days; however, Halloween falls in the middle of his study, and he notices that on Halloween, the children are especially active during his observation. Which threat to internal validity has confounded this study?

Question

Quizplus · Accepted Answer

The presence of Halloween during the study is an external event that influences the behavior of the children beyond the study's control, thereby affecting the internal validity of the study. This is an example of the history threat to internal validity. The other options (subject selection bias, volunteerism, fatigue) do not apply to the situation described.

Dr Feliciano Is Conducting a Study of Sleep on Children's