I would like to compare two groups (treatment: yes/no) at one point of time (end of the program) on four dependent variables (of which two seem to correlate with each other). Additionally, I have two control variables (which I suppose moderate the effect of treatment). I have roughly 100 participants divided between the two groups (not totally equal). The overall idea is comparing four different skills of two similar groups of which one received an educational program.

I have found some parametric tests in the internet which I found to be useful (multivariate multiple linear regression; hierarchical regression analysis with two layers; principal component regression; partial least square regression). The problem is, almost none of the assumptions are met (and frankly; I also did not understand which test would have been better for what reason). As I was searching for non-parametric tests, I only found robust t-tests or Kruskal-Wallis-test/Jonckheere-Terpstra Test (but I only have two groups; can I include covariates there, though), but those do not seem to allow controlling for other variables.

I have also heard of a possibility to transform my data with a Log to normally distributed data (so that I could use parametric tests), but was told that most likely it would not work for all my variables. To be honest, I did not really understand why. What do you think of it and could you please explain?

I work with SPSS (and in worst case could maybe try R, but would really prefer not to).

Could anyone please help me in choosing the right (non-parametric) test? Thank you so much!