[R] Anova with Scheffe Tests

[Simon Blomberg]

I stand corrected, although confidence.ellipse is a plotting 
function, and may not be quite what the questioner had in mind.

Cheers,

Simon.

>See confidence.ellipse() in the car() package. (Found from an R site search
>on "Scheffe")
>
>-- Bert Gunter
>Genentech Non-Clinical Statistics
>South San Francisco, CA
>
>"The business of the statistician is to catalyze the scientific learning
>process."  - George E. P. Box
>
>
>
>>  -----Original Message-----
>>  From: r-help-bounces at stat.math.ethz.ch
>>  [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Simon Blomberg
>>  Sent: Tuesday, March 01, 2005 4:25 PM
>>  To: samferguson at ihug.com.au; R-help at stat.math.ethz.ch
>>  Subject: Re: [R] Anova with Scheffe Tests
>>
>>  Hi,
>>
>>  I don't think there are any packages on CRAN that implement Scheffe's
>>  test. If you don't mind using another multiple comparisons procedure,
>>  you could look at ?TukeyHSD and/or the multcomp package.
>>  Alternatively, you could write your own function to do Scheffe's
>>  test. At least one other person has done that. See the following post
>>  in the R-help archive
>>  http://finzi.psych.upenn.edu/R/Rhelp02a/archive/19393.html. I can't
>>  vouch for whether that person's function works properly, but it
>>  shouldn't be hard to hand-check it, and improve it. You could search
>>  R-help yourself and maybe come up with other solutions.
>>
>>  Cheers,
>>
>>  Simon.
>>
>>  >Hi R-people,
>>  >
>>  >I am wanting to run Factorial ANOVA followed by Scheffe tests on
>>  >some spatial subjective data. I'm comparing X-Y independent
>>  >coordinates against x-y dependent coordinates. There are only four
>>  >independent spatial coordinates that form a square.
>>  >
>>  >I am wondering whether I am doing the right thing, because there
>>  >doesn't seem to be a simple way of doing this. I have attempted to
>>  >read `Practical regression and ANOVA using R' and am still confused.
>>  >
>>  >In good ol' Statview (now dearly departed) to complete a Scheffe
>>  >test you selected the independent variables and dependent variable
>>  >and it produced a  table with the pairwise comparisons of the levels
>>  >of the factor. I'm looking for a system that is as basic, but can be
>>  >done using R and has documentation so I'm not guessing what I'm
>>  >doing. I'd rather not have to do plots in R and then run over to
>>  >dead software to do Scheffe's if possible.
>>  >
>>  >I checked on google and there seems to be code for a couple of
>>  >functions out there, but I need something that has a manual.
>>  >
>>  >Is there a Scheffe function out there that is reasonably well
>>  >documented, or should I consider some other method of dealing with
>>  >this data. We have been using Scheffe for this type of analysis as I
>>  >was under the impression it was very conservative. Tukey's HSD seems
>>  >to be conservative as well. Should I try this? Is there a different
>>  >approacch that is better and where can I read about it.
>>  >
>>  >Thanks for any help you can provide.
>>  >
>>  >Sam
>>  >
>>  >______________________________________________
>>  >R-help at stat.math.ethz.ch mailing list
>>  >https://stat.ethz.ch/mailman/listinfo/r-help
>>  >PLEASE do read the posting guide!
>>  http://www.R-project.org/posting-guide.html
>>
>>
>>  --
>>  Simon Blomberg, B.Sc.(Hons.), Ph.D, M.App.Stat.
>>  Visiting Fellow
>>  School of Botany & Zoology
>>  The Australian National University
>>  Canberra ACT 0200
>>  Australia
>>
>>  T: +61 2 6125 8057  email: Simon.Blomberg at anu.edu.au
>>  F: +61 2 6125 5573
>>
>>  CRICOS Provider # 00120C
>>
>>  ______________________________________________
>>  R-help at stat.math.ethz.ch mailing list
>>  https://stat.ethz.ch/mailman/listinfo/r-help
>>  PLEASE do read the posting guide!
>>  http://www.R-project.org/posting-guide.html
>>


-- 
Simon Blomberg, B.Sc.(Hons.), Ph.D, M.App.Stat.
Visiting Fellow
School of Botany & Zoology
The Australian National University
Canberra ACT 0200
Australia

T: +61 2 6125 8057  email: Simon.Blomberg at anu.edu.au
F: +61 2 6125 5573

CRICOS Provider # 00120C