General Linear Model (GLM)

Graphs - Residuals versus Fits

  

This graph plots the residuals versus the fitted values. The residuals should be scattered randomly about zero. Use this plot to look for the following:

This pattern...

Indicates...

Fanning or uneven spreading of residuals across fitted values

Nonconstant variance

Curvilinear

A missing higher-order term

A point far away from zero

An outlier

 

Example Output

image\glmsrp3n.gif

Interpretation

Based on this plot, the residuals appear to be randomly scattered about zero. No evidence of nonconstant variance, missing terms, or outliers exists.