# Adjusted R^2 for regression with dummy variables

I'm familiar with R^2 and adj R^2 for penalizing the addition of predictive variables in a regression.

I just want to double check that If I have three continuous predictor variables and 30 dummy variables to reflect 31 categories of the data how I should be using the equation below

adj R^2 = 1-(1-r^2)((n-1)/(n-k+1))


where

n is my number of samples

n = 1056


and s is my number of variables

s = 3 + 30


thanks

• I have checked on google, just can't find anything specifically dealing with how to handle dummy variables in the calculation. – Hugh_Kelley Apr 23 at 9:41