Let's say group A (n = 57) is independent from group B (n = 17). The distribution of group A is non-normal (Shapiro-Wilk Test p-val = 0.004) & the distribution of group B is also non-normal (Shapiro-Wilk Test p-val = 0.02). The sample size n = 57 is large enough that I can assume normality for the distribution of group A. I want to compare the distributions of group A & group B. What hypothesis test would I use? Would I use the Welch's two-sample t-test, or the Mann-Whitney U-test? Why?