Calculation of RAB2 and RA2 is based on the residual variance (VAB = 20.2417); however, the random effect variance must be held at the values shown in Table 5 when running the A-only and null models in order to accurately measure the reduction of residual variance. Using the parms statement, the covariance dataset from the full AB model can be read into in the VA and Vnull, in order to fix the random effect variance. The following syntax runs the mixed models, holding the random effects constant, merges the residual variance from each model, and calculates RAB2, R - SQ2, and Cohen’s f 2 for smoking quantity across all assessment waves.
