When modeling E(y) with a single qualitative independent variable, the number $0 - 1$ dummy variables in the model is equal to the number of levels of the qualitative variable.

Question

When modeling E(y) with a single qualitative independent variable, the number  $0 - 1$ dummy variables in the model is equal to the number of levels of the qualitative variable.

Quizplus · Accepted Answer

When modeling with a single qualitative independent variable, the number of $0 - 1$ dummy variables is equal to the number of levels minus one. This is because one level is used as a reference category.

When Modeling E(y) with a Single Qualitative Independent Variable, the Number