In order to use the output from a multiple regression analysis to perform the ANOVA test on the difference among the means of four populations, how many dummy variables are needed to indicate treatments?
A) 1
B) 2
C) 3
D) 4

Question

Quizplus · Accepted Answer

To compare the means of four groups using multiple regression analysis, you need to create dummy variables for the groups. Since one group can serve as a reference category, you only need $n - 1$ dummy variables for $n$ groups. Therefore, for four groups, you need $4 - 1 = 3$ dummy variables.

In Order to Use the Output from a Multiple Regression