Residuals are computed as observed dependent variable values minus the predicted values from the ANOVA model. Studying the residuals can help you decide on the validity of the assumptions underlying the ANOVA model, namely, that the errors are approximately normally distributed and independent. This option creates quantile -quantile plots (see Q-Q Plot s ) and Scatterplot s of the standardized residuals from the ANOVA model fits. These plots are useful for assessing the quality of each fit.Caution : This option creates a large SAS data set and opens it in JMP for plotting. It can greatly slow execution time for large trials.