APA Dictionary of Psychology

in an analysis of variance, a value formed from the ratio of the largest variance over the smallest variance from the set of groups being assessed. The F_max statistic is assessed for significance by looking up the critical value in a statistical table for the relevant number of groups and degrees of freedom. If the calculated F_max statistic is larger than the critical valve, then there is evidence of heterogeneity of variance, which violates one of the assumptions of the analysis and renders its results invalid.