RE: [R] Anova with Scheffe Tests

From: Simon Blomberg <Simon.Blomberg_at_anu.edu.au>
Date: Wed 02 Mar 2005 - 12:04:49 EST

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@stat.math.ethz.ch
>> [mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of Simon Blomberg
>> Sent: Tuesday, March 01, 2005 4:25 PM

>> To: samferguson@ihug.com.au; R-help@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
>> >
>> >______________________________________________
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>> >https://stat.ethz.ch/mailman/listinfo/r-help
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>>
>>
>> --
>> 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@anu.edu.au
>> F: +61 2 6125 5573
>>
>> CRICOS Provider # 00120C
>>
>> ______________________________________________
>> R-help@stat.math.ethz.ch mailing list
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>> PLEASE do read the posting guide!
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>>

-- 
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@anu.edu.au
F: +61 2 6125 5573

CRICOS Provider # 00120C

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Received on Wed Mar 02 12:10:19 2005

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