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Hi, Anyone knows any existing package/program that has implemented unbiased (or bias-reduced) sandwich variance estimator (Wu (1986) and Carroll (2001) for GEE estimates? Thanks Qiong

Hi, Does anyone know how to make the color of the lines all black when plotting groupedData with an outer factor: For example, library(nlme) plot(Dialyzer, outer=~QB, key=F) This generated colored curves in R.2.4.1...

Hi, The standard error from logistic regression is slightly different from the naive SE from GEE under independence working correlation structure. Shouldn't they be identical? Anyone has insight about this? Thanks, Qiong a<-rbinom(1000,1) b<-rbinom(1000...

Hi, I could not use 'exlcude=' option in factor() to exclude a level from a existing factor. x is a factor: > x [1] a b c Levels: a b c > factor(x,exclude="c") [1] a b c Levels: a...

Problem solved. Thanks a lot for your replies! > x [1] a b c Levels: a b c > factor(as.character(x),exclude="c") [1] a b <NA> Levels: a b "exclude=" option may not work on factors. One has to...

Hi, I had a problem with the lmekin() in Kinship package: lmekin() can not be wrapped into another function For example: library(kinship) #creat an example dataset xx<-rnorm(100);yy<-rnorm(100) ;id<-1:100; test.dat<-as.data...

Hi, I had a problem with the lmekin() in kinship package: lmekin() can not be wrapped into another function library(kinship) #creat an example dataset xx<-rnorm(100) yy<-rnorm(100) id<-1:100 test.dat<-as.data.frame(cbind...

Thanks Thomas. Here is a further question I asked and the answer from Prof Ripley. This agrees with your previous response. Is it true that the same algorithm was used in calculation of GLM S.E. and GEE naive S...