If there are 6 independent variables, then there are ______ possible regressions with 2 predictors and ______ possible regressions with 3 predictors.
A)12; 18
B)15; 18
C)12; 20
D)18; 20
E)15; 20

Question

Quizplus · Accepted Answer

The number of possible regressions with 2 predictors out of 6 is calculated using combinations (since the order in which we select the predictors does not matter), which is 6 choose 2 = 6! / (2!(6-2)!) = 15. For 3 predictors, it's 6 choose 3 = 6! / (3!(6-3)!) = 20.

If There Are 6 Independent Variables, Then There Are ______