[R] model.tables error from aov

Prof Brian Ripley ripley at stats.ox.ac.uk
Tue Dec 16 21:58:12 CET 2008


Your design seems to be unbalanced: multistatum aov is intended for 
balanced designs.  My guess is that one idio subject has two Type=1 
observations: in which case try removing one of them.

On Tue, 16 Dec 2008, Harlan Harris wrote:

> Hi, I'm a new R user, coming from SPSS, and without a particularly strong
> stats background.
>
> I've got a data set that I'd like to do a mixed-design ANOVA with. No
> missing values. Here's the summary:
>
> summary(learnDat.ae)
> Type      Subject        idio     struct     TrainErrs            cond
> 0:20   11     : 3   idio   :28   ae  :58   Min.   : 0.00   idioae   :28
> 2:19   12     : 3   nonidio:30   fact: 0   1st Qu.: 6.25   idiofact : 0
> 3:19   14     : 3                          Median :11.50   nonidioae:30
>        15     : 3                          Mean   :13.40
>        18     : 3                          3rd Qu.:16.00
>        2      : 3                          Max.   :59.00
>        (Other):40
>
> Note that the TrainErrs column is the only numeric column, and I forced
> everything else to be a factor. (Is that correct?)
>
> I then do the following:
>
> aov.errs.ae <- aov(TrainErrs ~ (idio*Type) + Error(Subject/Type) + (idio),
> learnDat.ae)
>
> So, idio is between-subjects and Type is within-subjects. This is based on
> examples I've found elsewhere.
>
> summary(aov.errs.ae)
>
> This seems to work fine:
>
> Error: Subject
>          Df Sum Sq Mean Sq F value Pr(>F)
> idio       1    179     179    0.89   0.36
> Type       1    210     210    1.05   0.32
> Residuals 17   3401     200
>
> Error: Subject:Type
>          Df Sum Sq Mean Sq F value Pr(>F)
> Type       2    515     258    2.44  0.103
> idio:Type  2    680     340    3.22  0.053 .
> Residuals 34   3595     106
> ---
> Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
>
>
> Now the problem:
>
>> model.tables(aov.errs.ae,"means")
> Error in outer(rownames(efficiency), colnames(efficiency), paste)[eff.used]
> :
>  invalid subscript type 'list'
> In addition: Warning message:
> In any(efficiency) : coercing argument of type 'double' to logical
>
> All the examples and manuals I've found said this should work. When I did a
> fully between-subjects ANOVA on another data set, I had no problem with
> model.tables. I have no idea what to make of this error message. I've tried
> a number of variations on things, with no improvement.
>
> This is R version 2.7.2 (2008-08-25), running on Redhat, x86_64.
>
> Suggestions? Thanks!
>
> -Harlan
>
> 	[[alternative HTML version deleted]]
>
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>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
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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