**Group 1:**went from nothing, to receiving surgery 1, and then later on received surgery 2.

-> A (before), B (after first surgery), C (after second surgery)

**Group 2:**went from nothing to receiving surgery 1

-> A (before), B (after first/only surgery)

These patients have answered questionnaires with several questions and outcomes, at each relevant moment in time (A, B, and C for group 1 only). These outcomes are different, most variables are discrete, one is binomial ("have this affected you positively: yes or no").

Mainly I want to compare outcomes in group 1; was the effect significant after first surgery vs before, or after second surgery vs after first surgery. The data is in most cases not normally distributed.

*Question 1:*for comparison in between the same group, since the data is not normally distributed, when comparing for example outcome X in time A vs time B, is it correct to use the Wilcoxon one sample test?

*Question 2:*if one outcome is normally distributed, and one outcome is not (for example outcome x in time A is normally distributed but outcome x in time B is not), do I still use the Wilcoxon one sample test?

*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)?

*Question 4:*When comparing the binomial outcome within groups and in between group 1 and group 2, is it the Chi^2 test in both cases, or in neither?

*Question 5:*Which is the most reliable/easiest method to evaluate whether the data is normally distributed in STATA?