In research studies, the term "effect size" refers to
A)how much each treated and untreated person in the study changes.
B)the power of the statistical tests that are used to detect the impact of the independent variable.
C)how many subjects are included in a particular study.
D)the degree of external validity that the study has.

Question

Quizplus · Accepted Answer

Effect size refers to the magnitude of the difference between two groups in a research study. It is a measure of how much the independent variable (treatment) has affected the dependent variable (outcome). Option A correctly defines effect size in relation to the changes observed in treated and untreated individuals. Option B refers to the statistical power of the study, which is not the same as effect size. Option C is irrelevant to the concept of effect size, and option D is incorrect as external validity is not related to effect size.

In Research Studies, the Term "Effect Size" Refers to