My survey collected data from 384 respondents, and I have an overall score for each of them on each variable. Therefore, I'm working with 3 composite variables at the scale/ratio level. I want to know what the relationship between these 3 variables is. Unfortunately, my data violates many of the Pearson's and Linear Regression assumptions: non-normal distribution, non-linear or monotonic relationship, outliers. I can't seem to find an appropriate test. Any suggestions? (FYI, not a stats pro so layman's language appreciated).