Cohen's d

Cohen's d is a statistical measure that shows how much two groups differ in terms of their averages, relative to the variation within those groups. Think of it as a way to gauge the size of a difference—whether it's small, moderate, or large—by comparing the difference between the group averages to the typical variability among individuals. For example, a Cohen's d of 0.5 means the two groups' averages differ by half a standard unit, indicating a moderate difference. It helps researchers understand whether an observed difference is meaningful or just due to chance.