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 "Voc? v? as coisas como elas s?o e pergunta: por qu?? Mas eu sonho com coisas que nunca foram e pergunto: por que n?o? " - Bernard Shaw