[BioC] Factorial experiment: No degree of freedom in maanova
Naomi Altman
naomi at stat.psu.edu
Wed Feb 20 16:00:35 CET 2008
I have not used MAANOVA, but I think the problem
is probably that you included Sample in your model.
--Naomi
At 01:03 PM 2/19/2008, Marcelo Laia wrote:
>Hi,
>
>We have a factorial experiment like this:
>
>2 Varieties (resistant and susceptible)
>2 Conditions (with inductor and with H2O)
>2 Treatments (inoculated and non inoculated)
>4 Times points
>3 biological repetitions
>96 arrays (one color)
>
>We start to run the analysis on maanova package.
>
>In our design file design.txt there are these columns:
>
>Array Dye Var ind Trat Time Sample
>1 1 Res H2O Inoc 6h 1
>(...)
>96 1 Susc Ind N_inoc 48h 3
>
>We had been adjusted these model:
>
>anova.full.mix <- fitmaanova(data=leonardo.raw.averaged,
>+ formula=~Var+ind+Trat+Time+Var:ind+Var:Trat+Var:Time+
>+ ind:Trat+ind:Time+Trat:Time+Sample, random=~Sample)
>
>When we try to run the matest function,
>
>ftest.full.Var.mix = matest(leonardo.raw.averaged,anova.full.mix,
>+ term="Var",n.perm=100,test.method=rep(1,3))
>
> we got a "No degree of freedom" error.
>
>We only could do that if we remove the interactions from the formula
>in fitmaanova function!
>
>But, we like to get the interactions results.
>
>Are we doing anything wrong or is it impossible to fit a model to got
>the interactions?
>
>There are another way to got these interactions in our experiments?
>
>In try to insert Array in the formula (random), but the problem continues.
>
>Could you help?
>
>Is possible to got interactions results in our experiments?
>
>Any comments is very appreciated!
>
>Thank you very much
>
>--
>Marcelo Luiz de Laia
>Jaboticabal - SP - Brazil
>
>"Você vê as coisas como elas são e pergunta: por quê? Mas eu sonho com
>coisas que nunca foram e pergunto: por que não? " - Bernard Shaw
>
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Naomi S. Altman 814-865-3791 (voice)
Associate Professor
Dept. of Statistics 814-863-7114 (fax)
Penn State University 814-865-1348 (Statistics)
University Park, PA 16802-2111
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