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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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