What do you mean by discrete outcome variables? Rating score?outcomes are different, most variables are discrete, one is binomial ("have this affected you positively: yes or no").

Well, distribution of the raw data is almost never of interest (for example. in pre-post-data, it is theThe data is in most casesnot normally distributed.differencewhich sometimes might be looked at), but in your case, normality or non-normality is no issue at all, from the beginning, since you do not have interval scaled data. How large are your sample sizes?

This test requires interval scaled data, which seemingly you do not have. For dichotomous items, you can usewhen comparing for example outcome X in time A vs time B, is it correct to use the Wilcoxon one sample test?McNemar's test. If the discrete variables = rating scale items, then for these you can use thesign test.

Again, no-one needs normally distributed data. In some cases the distribution within the respective groupos could be relevant. If you have n > 30 and interval scaled variables, you can use a t-test. If your data is ordinal, or sample size is small, then use the Mann-Whitney.Question 3:When comparing the two groups, for example outcome y at time A in group 1 vs the same in group 2, is it correct to use the Wilcoxon rank sum test (Mann-Whitney)? (if the data is not normally distributed)?

With kind regards

K.