[R] Games-Howell, Gabriel, Hochberg

[Claus Atzenbeck]

On Mon, 28 Nov 2005, Claus Atzenbeck wrote:

> I read a book about statistics in psychology. The authors use SPSS. They
> talk about post hoc tests after ANOVA finds significant effects:
>
>     - Gabriel's procedure (for equal or slightly different sample sizes)
>     - Hochberg's GT2 (for different sample sizes)
>     - Games-Howell procedure (for populations with unequal variances)
>
> I could not find them in R. Do they not exist in R or are there any
> equivalents?

I saw a message today by Brian Ripley at
<http://www.r-project.org/nocvs/mail/r-help/2002/0565.html> stating that
there are only a few multiple comparison tests in R.

How do you calculate post hoc multiple comparisons tests with R for
normal distributed samples with different variances?

Would you claim that I savely can use TukeyHSD even for unequal
variances?

Claus