I have forwarded comments on these issues, in a separate message that  
is entitled:

"Strata and Degrees of freedom in anova and multi-level modeling"

John Maindonald             email: john.maindonald@anu.edu.au
phone : +61 2 (6125)3473    fax  : +61 2(6125)5549
Mathematical Sciences Institute, Room 1194,
John Dedman Mathematical Sciences Building (Building 27)
Australian National University, Canberra ACT 0200.


On 15 Feb 2006, at 10:00 PM, r-help-request@stat.math.ethz.ch wrote:

> From: Peter Dalgaard <p.dalgaard@biostat.ku.dk>
> Date: 15 February 2006 3:26:27 AM
> To: WPhantom <wp1@tiscali.fr>
> Cc: r-help@stat.math.ethz.ch
> Subject: Re: [R] A concrete type I/III Sum of square problem
>
>
> WPhantom <wp1@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 Clément
>>
>> 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@stats.ox.ac.uk
>>
>> ______________________________________________
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>> PLEASE do read the posting guide! http://www.R-project.org/posting- 
>> guide.html
>>
>
> -- 
>    O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
>   c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
>  (*) \(*) -- University of Copenhagen   Denmark          Ph:  (+45)  
> 35327918
> ~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)                  FAX: (+45)  
> 35327907


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