check_normality {performance} | R Documentation |
Check model for (non-)normality of residuals.
check_normality(x, ...) ## S3 method for class 'merMod' check_normality(x, effects = c("fixed", "random"), ...)
x |
A model object. |
... |
Currently not used. |
effects |
Should normality for residuals ( |
check_normality()
calls stats::shapiro.test
and checks the
standardized residuals (or Studentized residuals for mixed models) for
normal distribution. Note that this formal test almost always yields
significant results for the distribution of residuals and visual inspection
(e.g. Q-Q plots) are preferable.
The p-value of the test statistics. A p-value < 0.05 indicates a significant deviation from normal distribution.
For mixed-effects models, studentized residuals, and not
standardized residuals, are used for the test. There is also a
plot()
-method
implemented in the
see-package.
m <<- lm(mpg ~ wt + cyl + gear + disp, data = mtcars) check_normality(m) # plot results if (require("see")) { x <- check_normality(m) plot(x) } ## Not run: # QQ-plot plot(check_normality(m), type = "qq") # PP-plot plot(check_normality(m), type = "pp") ## End(Not run)