[R] another statistical question

[Alexander Engelhardt]

Am 31.03.2011 15:46, schrieb Anna Lee:
> Dear List!
>
> I have a unverse (basic population) which is not normally distributed.
> Now from this universe I take some subsets. Each subset is normally
> distributed within itself. I now want to compare the subsets and see
> if they differ significantly. So what is my assumption - normal
> distributed data and therefore comparison of means, or non normal
> distributed data and therefore comparison of medians?

If you want to do an ANOVA, the assumption is normality /within/ the 
groups. That is, Y given X=x is normal distributed. Also, you want the 
same variance within each group (group = your subset = factor value).

Short answer: Means.
(I am only 95% certain)