On Jun 12, 2011, at 12:50 , eldor ado wrote:
dear r community...
it loks like i won't be able to reach homogenity of variance for my
dataset, so i end up with welch anova instead of regular anova.
documentation on this test is rather scarce, so maybe someone here can
enlighten me a bit:
- do i understand that no two-way implementation of the welch anova
has been developed yet?
Has the THEORY been developed? For complete data, I suppose you can formulate
it as a multivariate contrast test and employ Huynh-Feldt correction, but it is
not quite the obvious generalization. Otherwise, formulate as a mixed model
with error variance depending on treatment, but the degree-of-freedom
adjustments are not implemented in lme.
- is there a post-hoc test for welch anovas implemented in R?
Again, what does it mean?
pairwise.t.test(..., pool.sd = FALSE, var.eq = FALSE)
will do various pairwise comparison and allow simple corrections of the p value
(Bonferroni and close relatives).
thanks a lot,
lukas kohl
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Peter Dalgaard
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd@cbs.dk Priv: pda...@gmail.com
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
