At times it is desirable to have independent variables in the model that are qualitative rather than quantitative. This is easily handled in a regression framework ... between the size and type of ...

The regression results can then be interpreted in the context of the before-multiplying-out form of the model ... variables, or the square of an existing variable. A two-valued qualitative variable ...

The most commonly used regression model for analyzing event ... For a factor or categorical variable made of J levels or categories, we must create J-1 dummy variables or indicator variables ...