Moderator vs. mediator vs. confounding variable
In a study, exercise reduces depressive symptoms more strongly in adolescents than in older adults. In this relationship, age is acting as a:
Answer D: explanation for every choice
A
A confounding variable is related to both the independent and dependent variables and offers an alternative explanation. Here age changes how strong the effect is.
B
A mediator explains how or why the independent variable affects the outcome, for example exercise improving sleep, which reduces symptoms.
C
The dependent variable is the outcome measured: depressive symptoms.
D
Correct. A moderator changes the strength or direction of the relationship between the independent and dependent variables.
TakeawayMediator = the mechanism (how). Moderator = the condition (for whom, or when).
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID ps13.