Hi, we have a split-plot experiment in which we measured the yield of crop fields. The factors we studied were:
B : 3 blocks I : 2 main plots for presence of Irrigation V : 2 plots for Varieties N : 3 levels of Nitrogen Each block contains two plots (irrigated or not) . Each plot is divided into two secondary parcels for the two varieties. Each of these parcels is divided into three subplots corresponding to three ordered levels of nitrogen. We found in Venables & Ripley (Modern Applied Statistics with S-plus, 3rd edition) the multistratum model for the same type of dataset but for three levels (without the "Irrigation" partition): aov(Y~N*V+Error(B/V), qr=T) which we adapted to our model: aov(Y~N*V*I+Error(B/V/I)) In Pinheiro & Bates (Mixed-effect models in S and S-plus) and as we saw in the message "Re: lme and lmer syntax from Ronaldo Reis-Jr, Wed 26 Oct 2005", we fitted also the mixed model : lme(Y~N*V*I, random~1|B/V/I) On a random simulated response Y, we didn't obtain similar results - only one factor with the same F-value - from the "aov" function and the "lme" one (oppositely to the example used by Venables & Ripley and Pinheiro & Bates). Is there a mistake in one of our two models or an explanation of this difference? Thanks a lot in advance. Caroline Domerg and Frederic Chiroleu UMR 53 PVBMT (Peuplements Vegetaux et Bio-agresseurs en Milieu Tropical) CIRAD Pôle de Protection des Plantes (3P) - Saint-Pierre Ile de la Réunion ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
