Re: [R] planned comparisons for ANOVA

From: Darren Weber <>
Date: Tue 18 Jul 2006 - 09:17:40 EST

On 7/17/06, Richard M. Heiberger <> wrote:
> It looks to me like you are asking for the split= argument to
> the summary.aov method. Look at ?summary.aov and the
> "# Cochran and Cox (1957, p.164)" example.
> I have more examples in my book
> Statistical Analysis and Data Display
> Richard M. Heiberger and Burt Holland

Thanks for the additional advice. At first glance, your book looks good. However, I have only taken undergraduate studies in statistics (mostly taught by psychologists, not mathematicians), so the material is most likely beyond my comprehension. As a new user of R, it is difficult to understand the methods and utilities. The help pages are consistent with most gnu/linux tools, they provide the essential information, without much elaboration. Most of the text books for R are similar. I am more familiar with stats texts in psychology, where greater emphasis is placed on explanation (eg, Tabachnick & Fidell).

Anyhow, I can see now there are at least three utilities for contrasts - the contrast option to aov, fit.contrast, summary.aov, and estimable. I don't have any clear rationale for using one or the other. I guess what I need to do now is generate a small example dataset for which the planned comparison F values are known, to validate the output of one or another of these routines.

Thanks, Darren mailing list PLEASE do read the posting guide! Received on Tue Jul 18 09:25:29 2006

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