Premise: not very clever in statistics!
Data: I have quantitative data (two variables, A and B) on two small groups of subjects (both N=7); I'm going to perform a T-test to check differences about those groups. Before it, I run a normality test on data A and B of first group, using Matlab lillietest function. The test says A is normal (H0 holds), B is not (H0 rejected). Here are my data, followed by p values:
A B 0.000 0.125 1.500 0.125 2.375 1.125 2.375 0.125 5.625 0.250 4.250 0.000 0.750 0.000 p=0.37 p=0.008 H0=1 H0=0
I obtained similar results for second group. My conclusion is that I can perform t-test only for variable A, not for B.
Question 1) is my conclusion correct?
Question 2): given the very small dimension of sample size (n=7), how should I consider the normality test responses? Did I run a meaningful test? Is there a minimum sample size for it?