Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Difference between groups for many variables
Replies: 4   Last Post: May 17, 2006 1:13 AM

 Messages: [ Previous | Next ]
 ggorjan Posts: 18 Registered: 4/25/06
Difference between groups for many variables
Posted: May 11, 2006 3:24 AM

Hello!

I often get data where there is more than one variable per unit, say
height, body weight, etc. The task of the experiment is usually to test
for the differences between groups. I usually performed univariate
analysis with (generalized) linear model for each variable and
performed inference (estimated difference with corresponding intervals
and p-values) for each variables separately. In a seminar dissusion of
similar type of analysis a problem of multiple testing was brought up
and people mentioned that one should lower alpha via Bonferroni
correction. Can anyone please comment on this?

Is there any difference in approach to such type of post-hoc adjustment
between frequentist and Bayesian view of stats?

Additionally I was wondering if there is any better way to perform the
analysis. I was thinking about:
- multivariate analysis with linear models, where I would allow for
correlation between variables
- "true" multivariate analysis via Hotelling's T - I have never
performed such ...

Thanks!

--
Lep pozdrav / With regards,
Gregor Gorjanc

----------------------------------------------------------------------
University of Ljubljana PhD student
Biotechnical Faculty
Zootechnical Department URI: http://www.bfro.uni-lj.si/MR/ggorjan
Groblje 3 mail: gregor.gorjanc <at> bfro.uni-lj.si

SI-1230 Domzale tel: +386 (0)1 72 17 861
Slovenia, Europe fax: +386 (0)1 72 17 888

----------------------------------------------------------------------
"One must learn by doing the thing; for though you think you know it,
you have no certainty until you try." Sophocles ~ 450 B.C.
----------------------------------------------------------------------

Date Subject Author
5/11/06 ggorjan
5/11/06 Richard Ulrich
5/13/06 ggorjan
5/14/06 Art Kendall
5/17/06 Sullivan2000