[R] Three-way ANOVA shows me two-way results

[Mike Marchywka]

> From: tal.galili at gmail.com
> Date: Tue, 23 Nov 2010 18:14:39 +0200
> To: M.t.Hart at ai.rug.nl
> CC: r-help at r-project.org
> Subject: Re: [R] Three-way ANOVA shows me two-way results
>
> It seems your model defines more parameters then your data permits (e.g:
> singular).
>
 
if you do google search and search this page for "singular"
term dropping has precedent,
 
http://www.stata.com/help.cgi?test
 
Alt, see if you can formulate something non-singular enough to 
remove the warning and see if output is as expected.
 

> What you can do is try something like this:
>
> summary(aov(formula('FP ~ (lum + obj + man)^2 - Error(vp/(lum + obj +
> man)^2)),data=dataf))
>
> (notice the use of + and ^)
> This is something your data might permit (assuming this will answer
> questions you are interested in answering)
> Tal
>
>
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>
>
> On Tue, Nov 23, 2010 at 4:58 PM, Marius 't Hart wrote:
>
> > Hi all,
> >
> > I'm doing a 3-way ANOVA like this:
> >
> > summary(aov(formula('FP ~ (lum * obj * man)3 - Error(vp/(lum * obj *
> > man)3)'),data=dataf))
> >
> > But in the output I only get 1- and 2-way effects, like this one:
> >
> > Error: vp:obj:man
> > Df Sum Sq Mean Sq F value Pr(>F)
> > obj:man 1 1.5291e-34 1.5291e-34 5.7011 0.0542 .
> > Residuals 6 1.6093e-34 2.6822e-35
> > ---
> > Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
> >
> > (And a warning that the Error() model is singular.)
> >
> > What am I doing wrong so that I don't get the 3-way interactions I want
> > to look at?
> >
> > Thank you!
> >
> > Marius.
> >
> > [[alternative HTML version deleted]]
> >
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