I have a question regarding the appropriate use of comparisons for independent samples (3 factor levels). Overall sample size is N=546, subsamples: 218 or 228 or 100), convenience sampling, stratified.
I use ANOVA with post hoc Tukey, if Levene indicates variance homogeneity.
My question: If the variances are unequal, what to do?
a. Using Kruskal-Wallis? For post hoc: Do I use Mann-Whitney for pairwise comparisons (if so: what about the alpha inflation?)?
b. Still using GLM but with non-parametric post hocs? If so: which one? Tamhane? Dunnett or Games-Howell? What about F, can I still use it? Isn’t H then the more appropriate statistic? Why gives GLM anyway the option of running on-parametric tests of homoscedasticity is an assumption (I am confused)
Thanks for any input on this one