The number of dummy variables representing a qualitative variable should be ________.
A) one less than the number of categories of the variable
B) two less than the number of categories of the variable
C) the same number as the number of categories of the variable
D) None of these choices is correct.

Question

Quizplus · Accepted Answer

The number of dummy variables representing a qualitative variable should be one less than the number of categories of the variable. For example, if a qualitative variable has five categories, it should be represented by four dummy variables. Each of these four dummy variables would represent one of the five categories, with the fifth category being the "reference" category.

The Number of Dummy Variables Representing a Qualitative Variable Should