Question

A clinician claims that the effectiveness of a new treatment varies depending on the gender of the client. Specifically, the new treatment has been shown to be very effective for females, but the treatment has little or no effect for males. In this example,

a) Confounding variable
b) Interaction effect
c) Main effect
d) Placebo effect

Answer 1

The scenario described indicates an interaction effect because the treatment's effectiveness is influenced by the gender of the client, which acts distinctly on the results observed for males and females.

Step-by-step explanation:

The clinician's observation that the effectiveness of a new treatment varies depending on the gender of the client, with different effects observed for females versus males, represents an interaction effect. An interaction effect occurs in research when the effect of one independent variable on the dependent variable changes across the levels of another independent variable—in this case, gender modifies how the treatment works.

This is different from a main effect, where a treatment would show a consistent effect across all levels of another factor, and it is not a confounding variable, which would be an uncontrolled factor that might influence the treatment effectiveness. The placebo effect is also separate from this scenario; it refers to changes in participants' outcomes driven by their beliefs or expectations about the treatment, not by the treatment itself.