Re: [R] TukeyHSD fails on my data

From: Prof Brian Ripley <>
Date: Mon, 07 May 2007 21:41:51 +0100 (BST)

We don't have the data (nothing useful was attached - see the posting guide for what you can attach), but it looks like you should be using the 'which' argument to TukeyHSD.

On Mon, 7 May 2007, Gav Wood wrote:

> Howdo folks,
> So I have my data (attached). There are two columns I'm interested in;
> "algname" and "dur". I'd like to know how dur changes with algname. algname
> is nominal and there are 7 possibilities. There are two more nominal
> independents, "task" and "id", so my model is:
> dur ~ algname+task+id
> From the research I've done, a TukeyHSD seems to be what I need, so I do:
> TukeyHSD(aov(dur ~ algname+task+id, cstats), ordered=T)
> But I get this back:
> Error in, length(means)) : unimplemented type 'NULL' in 'rep'
> In addition: Warning messages:
> 1: non-factors ignored: task in: replications(paste("~", xx), data = mf)
> 2: non-factors ignored: id in: replications(paste("~", xx), data = mf)
> Can anyone shed any light on the situation?
> Gav

Brian D. Ripley,        
Professor of Applied Statistics,
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Mon 07 May 2007 - 20:46:10 GMT

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