I just ran a hierarchical multiple regression with 6 control variables, 3 main effects and 2 interaction effects. To determine the critical value for the Mahalanobis distance (for identifying outliers) I need the to know the number of predictor variables to determine the critical value. This is probably a pretty straightforward question! How many degrees of freedom are there in my case?
Here the guide to the Mahalanobis distance: https://en.wikiversity.org/wiki/Mahalanobis%27_distance
Thank you so much for your help!