This standardized measure of effect size is used in Analysis of Variance to characterize the overall level of population effects. It is the square root of the sum of squared standardized effects divided by the number of degrees of freedom for the effect. For example, in a One-Way ANOVA, the RMSSE is calculated as

RMSSE = sqrt{[S(aj/s)2]/J-1} = sqrt(sa2/s2) = sa/s

See also, Power Analysis.