[R] confidence interval calculation for gee

[Duncan Mackay]

At 04:26 8/04/2013, you wrote:
>Hello,
>I have the following r-codes for solving a quasilikelihood estimating
>equation:
>
> >library(geepack)
> >fit<-geese(y~x1+x2+x3,jack=TRUE,id=id,scale.fix=TRUE,data=dat,mean.link =
>"logit", corstr="independence")
>
>
>Now my question is how can I calculate the confidence interval of the
>parameters of the above model "fit"?
>
>         [[alternative HTML version deleted]]
>
>______________________________________________
>R-help at 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.

It pays to look at the help page. usually with a regression there is 
a summary method

 From ?geese and the index page of geepack there is summary.geese


names(summary(m2))
[1] "mean"        "correlation" 
"scale"       "call"        "model"       "control"     "error" 
"clusz"
 > summary(m2)[[1]]
               estimate    san.se       wald          p
(Intercept)  1.3476092 0.1573571 73.3423807 0.00000000
x            0.1118360 0.1159304  0.9306116 0.33470405
trt         -0.1068224 0.1936977  0.3041417 0.58129752
x:trt       -0.3023841 0.1710601  3.1247883 0.07710989

geepack uses sandwich standard errors (san.se)

summary(m2t)[[2]]
        estimate     san.se     wald            p
alpha 0.5978407 0.08107156 54.37934 1.653122e-13

HTH

Duncan

Duncan Mackay
Department of Agronomy and Soil Science
University of New England
Armidale NSW 2351
Email: home: mackay at northnet.com.au