Double Exponential Smoothing

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

$image\desm_5n.gif$

Interpretation

Based on this plot, the residuals do not appear to be randomly scattered about zero and there is an outlier in the bottom right corner of the plot. Evidence of nonconstant variance and outliers exists.