Modeling and Multivariate Methods - SAS

Chapter 7 Performing Logistic Regression on Nominal and Ordinal Responses 219
Example of an Ordinal Logistic Model
Details of modeling types are discussed in the Basic Analysis and Graphing book. The details of fitting appear
in the appendix “Statistical Details” on page 651. The method is discussed in Walker and Duncan (1967),
Nelson (1976), Harrell (1986), and McCullagh and Nelder (1983).
Note: If there are many response levels, the ordinal model is much faster to fit and uses less memory than
the nominal model.
As an example of ordinal logistic model fitting, McCullagh and Nelder (1983) report an experiment by
Newell to test whether various cheese additives (A to D) had an effect on taste. Taste was measured by a
tasting panel and recorded on an ordinal scale from 1 (strong dislike) to 9 (excellent taste). The data are in
the Cheese.jmp sample data table.
1. Open the Cheese.jmp sample data table.
2. Select Analyze > Fit Model.
3. Select Response and click Y.
4. Select Cheese and click Add.
5. Select Count and click Freq.
6. Click Run.
7. From the red triangle next to Ordinal Logistic Fit, select Wald Tests.