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 ...

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 ...

Researchers often suggest the usefulness of regression models of market response as aids to market decision making. Commonly, models which involve monthly, bimonthly, or quarterly data explicitly ...

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 ...