The error you had in your program was because of the na.action in the function call. If you specify the parameter you need to give it a function such as na.omit or na.fail
There would be a second error if you fixed this because you are including an intercept and the gee function will automatically fit an intercept also, this will lead to to columns being the exact same in the design matrix. The following code should get you where you want to be. eta <- rnorm(100) Si <- runif(100, min=0, max=11) lny <- 10+2*Si-Si^2+eta id <- (1:100) conc <- rep(1,100) Si2 <- Si^2 geedat <- data.frame(Si=Si,Si2=Si2,lny=lny,id=id) lnyhat <- gee(lny ~ Si - Si2, id=id, data=geedat) lnyhat <- gee(lny ~ conc+Si - Si2 -1, id=id, data=geedat) -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] Sent: Wednesday, August 18, 2004 14:54 PM To: [EMAIL PROTECTED] Subject: [R] Gee I am trying to learn the gee function in R. So I try to generate some data and use this function. I have the following lines: ######################################## Gee # Generating lny=10+2*Si-Si^2+eta # eta ~ N(0,1) # Si ~ U(0,11) eta <- vector(mode="numeric",100) eta <- rnorm(100) Si <- vector(mode="numeric",100) Si <- runif(100, min=0, max=11) lny <- vector(mode="numeric",100) lny <- 10+2*Si-Si^2+eta id <- vector(mode="numeric",100) id <- (1:100) cons <- vector(mode="numeric",100) for(i in 1:100) { cons[i] <- 1 } Si2 <- vector(mode="numeric",100) for(j in 1:100) { Si2[j] <- Si[j]^2 } geedat <- data.frame(Si=Si,Si2=Si2,lny=lny,id=id,cons=cons) lnyhat <- gee(lny~cons+Si-Si2, id=id, data=geedat, na.action) And I received the following error message: [1] "Beginning Cgee S-function, @(#) geeformula.q 4.13 98/01/27" Error in "[.data.frame"(structure(list(lny = c (9.92388214744737, 2.54332321404939, : invalid subscript type I don't know what I am doing wrong. May someone help me? Thanks Ana ______________________________________________ [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 ______________________________________________ [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
