A way to avoid the problem would be to test in a single step all dummy variables corresponding to the same categorical variable rather than one dummy variable at a time, such as in the analysis of ...

The use of dummy variables requires the imposition of additional constraints on the parameters of regression equations if determinate estimates are to be obtained. Among the possible constraints the ...

A natural question: When the qualitative variable takes k categorical values, why don't we simply encode it with k "yes/no" variables? Conceptually, this would work. Practically, it fails inside the ...

Regression with qualitative variables is different from analysis of variance and analysis of covariance. Analysis of variance uses qualitative independent variables only. Analysis of covariance uses ...

The CATMOD procedure can perform linear regression and logistic regression of response functions for data that can be represented in a contingency table. See Chapter 5, "Introduction to Categorical ...