Fit unequal variance model in R
Thanks a lot. The problem is solved. It took me a while to understand the output from the R. With little calculation, I am able to match results from R to SAS.
Dieter Menne wrote:
Feng Jingyu wrote:
I used gls and it still does not provide me different estimates of variance for each treatment group. Did I do anything wrong? lm3<-gls(GSI~treatment,data=z,weights=varIdent(form=~treatment),method="ML")
try weights = varIdent(form~1|treatment) See the example in library/nlme/scripts/ch05.r ,fm1Orth.gls Dieter
View this message in context: http://www.nabble.com/Fit-unequal-variance-model-in-R-tp22829549p22873995.html Sent from the R help mailing list archive at Nabble.com.