I hope you can help. I am working with numerical data and I wish to compare means.

Data set 1 has N=30 (normally distributed)

Data set 2 has N=24 (not normal)

Data set 3 has N=24 (not normal)

Data set 4 has N=12 (not normal)

I used the Shapiro Wilks test to test for normality and any p value < .05 was not normal.

I have to compare set 1 to set 2, set 1 to set 3 and set 1 to set 4.

Being that I am comparing a normal set to non-normal, which test should I use. I would think the Mann-Whitney Test but I want to be sure.

Thanks in advance for your help.