I am working on multiple regressions at the moment and have come to a point that I need a little assistance. I have the following question:

Is there a way to test for significant difference between 2 regression models?

That would mean testing for the difference between 2 R-Squared values?

If so, which test should I use? (partial F-test or F-test?). Assuming this cannot be done in SPSS, how does it work manually?

I know these are actually 3 questions but could someone help me out with this predicament (another question)?

Thanks so much!