Modeling and Multivariate Methods - SAS

70 Fitting Standard Least Squares Models Chapter 3
Estimates
Joint Factor Tests
This option appears when interaction effects are present. For each main effect in the model, JMP produces a
joint test on all the parameters involving that main effect.
Example of a Joint Factor Tests Report
1. Open the Big Class.jmp sample data table.
2. Select Analyze > Fit Model.
3. Select weight and click Y.
4. Select age, sex, and height and click Macros > Factorial to degree.
5. Click Run.
6. From the red triangle next to Response weight, select Estimates > Joint Factor Tests.
Figure 3.9 Joint Factor Tests for Big Class model
Note that age has 15 degrees of freedom; it is testing the five parameters for age, the five parameters for
age*sex, and the five parameters for height*age. All parameters tested to be zero.
Inverse Prediction
To find the value of x for a given y requires inverse prediction, sometimes called calibration. The Inverse
Prediction option on the Estimates menu lets you ask for the specific value of one independent (X)
variable given a specific value of a dependent variable and other x values (Figure 3.11). The inverse
prediction computation includes confidence limits (fiducial limits) on the prediction.
Example of Inverse Prediction
1. Open the Fitness.jmp sample data table.
2. Select Analyze > Fit Y by X.
3. Select Oxy and click Y, Response.
4. Select Runtime and click X, Factor.
When there is only a single X, as in this example, the Fit Y by X platform can give you a visual
approximation of the inverse prediction values.
5. Click OK.
6. From the red triangle menu, select Fit Line.