Use the Profiler, Contour Profiler, or Surface Profiler to gain further insight into the fitted model. To select a profiler option, click on the red triangle menu next to Loglinear Variance Fit and select one of the options under the Profilers menu.
Open the sample data table.
Select Analyze > Fit Model.
Click Run.
Prediction Intervals
MoldTemp to 0.2
Hold Time to -1
Profiler to Match Target and Minimize Variance
If Y is the modeled response, and you want a prediction interval for a new observation at xn, then:
s2|xn is the variance for the individual prediction at xn
s2Y|xn is the variance of the distribution of Y at xn
Because the variance of the individual prediction contains the variance of the distribution of Y, the effects of the changing variance for Y can be seen. Not only are the individual prediction intervals wider, but they can change shape with a change in the variance effects.