[SPSS - GLM-ANOVA] GLM-ANOVA an appropriate choice of statistics?

Dear Community!

I have two questions regarding the GLM-ANOVA and post hoc tests!

1 ) Is the GLM-ANOVA an appropriate choice of statistical analysis in my study?
2 ) Post hoc test: Fischer´s LSD vs. Bonferroni

Study design:
I have 4 groups of patients with different diagnosis in which I have collected 4 samples in a serie, 1 sample before surgery and 3 after. The groups of patients varies from n=5 to n=10.

I want to analyze the measured levels of circulating collagen type IV in the same group of patient regarding to the difference over time. I have used SPSS- univariate GLM-ANOVA to do this. Can I use the univariate GLM-ANOVA in this way? (I have tested the groups for normality. and they are normaly-distributed)

I provide data for one group to help clarify my question!

Post hoc I have used Fischers LSD test, which according to several sources is an outdated post hoc test and shouldn´t be used. When I use this I get significant differences, when I use the Bonferroni test I don´t. The Bonferroni test is more strict but I think it tends to overcorrect when the number of groups increases.

Thanks in advance,


Less is more. Stay pure. Stay poor.
Seems fine. Possible correction, you want your residuals to be normally distributed not the variables themselves (which can or cannot be ~ N).

Yes, Bonferroni is more cautious.