An experimenter tests the hypothesis that physical exercise improves mood. Subjects in the experimental group participate on Monday and Tuesday and those in the control group on Wednesday and Thursday. Which of the following is the extraneous variable?

Question

Quizplus · Accepted Answer

The day of the week is an extraneous variable because it introduces a potential source of variation that is not the independent variable being studied (exercise), which could affect the mood of participants differently across the groups.

An Experimenter Tests the Hypothesis That Physical Exercise Improves Mood