To test whether the normality assumption is violated, instead of only plotting the diagnostic plots, we can run crTest from DAMisc to compare the LOESS curve with the optimal PP/QQ line. This provides a significant p-value, if the normality assumption is violated in a way that the distribution significantly differs from the theoretically expect PP / QQ plot.
To test whether the normality assumption is violated, instead of only plotting the diagnostic plots, we can run crTest from DAMisc to compare the LOESS curve with the optimal PP/QQ line. This provides a significant p-value, if the normality assumption is violated in a way that the distribution significantly differs from the theoretically expect PP / QQ plot.