There is nothing about R in your question, hence it is not appropriate for this list. Please consult with a local statistician, or post on a stats help list such as http://stats.stackexchange.com/
On Tue, Jul 24, 2012 at 8:55 PM, tedtoal <twt...@ucdavis.edu> wrote: > I'm trying also to understand how to get the between-group variance out of a > one-way ANOVA, but I'm beginning to think that in a sense, the variance does > not exist. Emma said: > > *The model is response(i,j)= group(i)+ error(i,j)* > > Yes, if by group(i) you mean intercept + coefficient[i]. > > *we assume that group~N(0,P^2) and error~N(0,sigma^2) * > > Only the error is assumed to be a random variable. Group is a fixed effect, > not a random variable, and therefore it has no variance associated with it. > The model does not predict a variance for it. One could compute the > variance of the coefficients and call this a group variance, but it seems to > me that isn't the right way to think about it. > > I'm trying to calculate a heritability value for a trait in an organism, > defined as Vg/Vp, where Vg = variance due to genotype and Vp = total > variance. The model is p~g, or p[i,j] = intercept + g_coefficient[i] + > error[i,j]. But to get Vg, I think it is actually necessary to use a > different model, where g is modelled as a random variable (a random effect), > so the model can estimate a variance associated with it. > > If anyone can add something to this, please do. > ted > > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/Between-group-variance-from-ANOVA-tp901535p4637686.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help@r-project.org 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. ______________________________________________ R-help@r-project.org 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.