I got the answer: weights=varComb(varFixed(~1/n),varPower(~Age))
Bond, Stephen-2 wrote: > > Hello everybody, > > I have a dataset where each row has number of subjects and that gives me > natural weights for the variance function. Additionally I see that > variance increases with Age, which is a regressor. > So using gls I have > > > > weights=varFixed(~1/n) > > but don't know how to include the extra effect of the regressor. > Fitted values show a quadratic curve vs. age, not sure if that helps. > > Thanks everybody. > Stephen > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. > > -- View this message in context: http://www.nabble.com/how-to-specify-two-variance-effects-in-gls-tp25044356p25061604.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.