Modeling and Multivariate Methods - SAS

202 Performing Logistic Regression on Nominal and Ordinal Responses Chapter 7
The Logistic Fit Report
Figure 7.3 Whole Model Test
The Whole Model table shows these quantities:
Model lists the model labels called Difference (difference between the Full model and the Reduced
model), Full (model that includes the intercepts and all effects), and Reduced (the model that includes
only the intercepts).
–LogLikelihood records an associated negative log-likelihood for each of the models.
Difference is the difference between the Reduced and Full models. It measures the significance of the
regressors as a whole to the fit.
Full describes the negative log-likelihood for the complete model.
Reduced describes the negative log-likelihood that results from a model with only intercept parameters.
For the ingot experiment, the –LogLikelihood for the reduced model that includes only the intercepts is
53.49.
DF records an associated degrees of freedom (DF) for the Difference between the Full and Reduced model.
For the ingots experiment, there are two parameters that represent different heating and soaking times,
so there are 2 degrees of freedom.
Chi-Square is the Likelihood-ratio Chi-square test for the hypothesis that all regression parameters are
zero. It is computed by taking twice the difference in negative log-likelihoods between the fitted model
and the reduced model that has only intercepts.