Hi,
I am doing comparison between two independent groups; patient group of 24 subjects and control group of 34 subjects. My questions are:
1) Is testing normality relative? I mean is it sufficient to check out visually the histograms and q-q plots and decide if my variable data shows normality or not? what are skewness and kurtosis? I wonder what is the conclusive tests that I can depend on to test normality.
2) In case one group is showing normality while the other is not, does that means that my data is not normally distributed and I have to use non-parametric testing?
3) I read about other assumptions regarding using parametric tests even the variable data of both groups shows normal distribution. For example, I read about variance homogeneity? How can I check this out? I am using SPSS for my data analysis.
Thank you.