Regression - Diagnostic - Plot - Normal Q-Q

A Normal Quantile-Quantile chart. This reveals departures from the normality assumption. Where the residuals are normally distributed, the points on the line will form an approximately straight line running from the bottom-left to the top-right. Shapes other than a straight line indicate that the normality assumption may not have been satisfied. See this answer on Cross Validated for more information.

Example

An example Q-Q plot output from running this QScript on a linear regression model is shown below.

Acknowledgements

Uses plot.lm and/or plot.glm function from the stats R package.

Code

includeWeb("QScript R Output Functions");

const menu_location = "Regression > Diagnostic > Plot > Normal Q-Q";
createDiagnosticROutputFromSelection(menu_location);