[R] A concrete type I/III Sum of square problem

[Peter Dalgaard]

WPhantom <wp1 at tiscali.fr> writes:

> Thanks Brian for the reference.
>   I just discover that it is available in our 
> library so I going to take it & read it soon.
> Actually, I don't even know the difference 
> between a multistratum vs a single-stratum AOV. A 
> quick search on google returned me the R materials so that I imagine
> that these concepts are quite specific to R.

You have to be careful not to confuse Google's view of the world with
Reality...

The concept of error strata is much older than R, and existed for
instance in Genstat, anno 1977 or so. However, Genstat seems to have
left little impression on the Internet. 
 
> I will read the book first before asking for more informations.

The executive summary is that the concept of error strata relies
substantially on having a balanced design (at least for the random
effects), so that the analysis can be decomposed into analyses of
means, contrasts, and contrasts of means. For unbalanced designs, you
usually get meaningless analyses.


> Thanks
> 
> Sylvain Clément
> 
> At 12:38 14/02/2006, you wrote:
> >More to the point, you are confusing 
> >multistratum AOV with single-stratuam AOV.  For 
> >a good tutorial, see MASS4 (bibliographic 
> >information in the R FAQ).  For unbalanced data 
> >we suggest you use lme() instead.
> >
> >--
> >Brian D. Ripley,                  ripley at stats.ox.ac.uk
> 
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   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
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