This question is about a regression analysis that I want to run, but I am not too familiar with this type of analysis.

I have conducted MANOVAs to isolate variables that are significant out of the ones that were theoretically relevant for my analysis. I would now like to conduct regression analyses to see if these variables predict a different outcome, but I am wondering if I should include all of my theoretically-relevant variables that I initially used for the MANOVAs or whether it would make more sense to only include the variables that came out significant.

J.