I'm not a statistician, so take what I say with a grain of salt. On 12/02/04 06:29, Rene Eschen wrote: >Can someone explain me why factor C has only 25 Df (in stead of 28, what I >expected), and why this number changes when I leave out factors B or C (but >not A)? Why do factors B and C (but again: not A) not show up in the >calculation if they appear later in the formula than D? > >When I ask summary.lm(aov(Y~A+B+C+D+E)), R tells me that three levels of D >were not defined because of "singularities" (what does this word mean?). >After checking and playing around with the dataset, I find no logical reason >for which levels are not defined. Even if I construct a "perfect" dataset >(balanced, no missing values) I never get the correct number of Df.
I would guess that the factors are somewhat predictable from each other. That is, there is some redundancy. Try predicting each factor from all the others, without the dependent variable. Jon -- Jonathan Baron, Professor of Psychology, University of Pennsylvania Home page: http://www.sas.upenn.edu/~baron R search page: http://finzi.psych.upenn.edu/ ______________________________________________ [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
