Calculating Cohen’s f 2 in Eq. 2 requires both RAB2 and RA2, thus several variants of the regression must be run in order to obtain VAB (residual variance of the model containing A and B together), VA (residual variance of the model without B) for each B, and Vnull (residual variance of the model without regressors). Once these residual variances are obtained, RAB2 and RA2 can be calculated as in Eq. 3, and these in turn can be used to calculate Cohen’s f 2 as in Eq. 2.
