[R] A concrete type I/III Sum of square problem
Gregor Gorjanc
gregor.gorjanc at gmail.com
Thu Feb 16 07:37:20 CET 2006
> 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.
>
Can you (prof. Dalgaard) please point us to relevant book with these
topics. I am very interested in it since my data are often unbalanced.
>>> Thanks
>>>
>>> Sylvain Cl?ment
>>>
>>> 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.
I do not have the whole book in my head as prof. Ripley probably does,
but I can not recall to read about this in MASS4. I am sure I am wrong
and would you (prof. Ripley) be please so kind and point us to relevant
chapters/pages.
Many thanks.
--
Lep pozdrav / With regards,
Gregor Gorjanc
----------------------------------------------------------------------
University of Ljubljana PhD student
Biotechnical Faculty
Zootechnical Department URI: http://www.bfro.uni-lj.si/MR/ggorjan
Groblje 3 mail: gregor.gorjanc <at> bfro.uni-lj.si
SI-1230 Domzale tel: +386 (0)1 72 17 861
Slovenia, Europe fax: +386 (0)1 72 17 888
----------------------------------------------------------------------
"One must learn by doing the thing; for though you think you know it,
you have no certainty until you try." Sophocles ~ 450 B.C.
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