Suppose you are interested in controlling for a student's eye color in a regression explaining variation in standardized test scores.If eye color is defined as Blue,Green,Brown,or Other then how many dummy variables should you include in your analysis?
A)1.
B)2.
C)3.
D)4.

Question

Quizplus · Accepted Answer

To control for a categorical variable with four categories (Blue, Green, Brown, or Other) in a regression model, you need to include one fewer dummy variable than the number of categories to avoid the dummy variable trap. Therefore, for four categories, you should include three dummy variables.

Suppose You Are Interested in Controlling for a Student's Eye