Regression - Diagnostic - Plot - Normal Q-Q extension

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Create a normal Quantile-Quantile (QQ) plot to reveal departures of the residuals from normality

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 modellinear 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";
errorIfExtensionsUnavailableInQVersion(menu_location);
createDiagnosticROutputFromSelection(menu_location);