Modeling and Multivariate Methods - SAS

72 Fitting Standard Least Squares Models Chapter 3
Estimates
7. Click OK.
The Inverse Prediction report (Figure 3.12) gives the exact predictions for each Oxy value specified with
upper and lower 95% confidence limits. The exact prediction for Runtime when Oxy is 50 is 9.7935. This
value is close to the approximate prediction of 9.779 found in Figure 3.10.
Figure 3.12 Inverse Prediction Given by the Fit Model Platform
Note: The fiducial confidence limits are formed by Fieller’s method. Sometimes this method results in a
degenerate (outside) interval, or an infinite interval, for one or both sides of an interval. When this happens
for both sides, Wald intervals are used. If it happens for only one side, the Fieller method is still used and a
missing value is returned. See the “Statistical Details” on page 651 appendix.
The inverse prediction option also predicts a single x value when there are multiple effects in the model.
To predict a single x, you supply one or more y values of interest. You also set the x value that you predict is
missing. By default, the other x values are set to the regressor’s means but can be changed to any desirable
value.
Example Predicting a Single X Value with Multiple Model Effects
1. From the Fitness.jmp sample data table, select Analyze > Fit Model.
2. Select Oxy and click Y.
3. Add Runtime, RunPulse, and RstPulse as effects.
4. Click Run.
5. From the red triangle menu next to Response Oxy, select Estimates > Inverse Prediction.