Denominator degrees of freedom were based on the Sattherthwaite approximation; time value for initial assessments in all analyses was set to zero, and time was modeled by sequential assessment occasion. Effect sizes, converted to Cohen’s d (Cohen, 1992), were derived for overall F-test statistics as suggested by Rosenthal and Rosnow (1991). Effect sizes for within-group contrasts were calculated following Wackerly, Mendenhall, and Scheaffer (2008, p. 271).
