[R] variance covariance matrix in GLM
markleeds at verizon.net
markleeds at verizon.net
Thu Aug 28 19:16:14 CEST 2008
this is for the person who asked me about prediction confidence
intervals in a GLM because I lost your email. Below follows a simple
example in CAR and the variance covariance of the beta coefficients is
in the summary. So, I think, given that output, it should be pretty
straightforward to do what you want. I also bet that code for what you
want to do is in some function in John's effects package but I haven't
looked at the code. If it's not possible to find it in John's code, ( I
think prediction intervals have an extra term in the formula for the CI
because of the error term variance ) that formula should be in any
decent regression text book. Good luck.
#========================================================================================
attach(Mroz)
model.mroz<-glm(lfp ~ k5 + k618 + age + wc + hc + lwg + inc,
family=binomial)
print(model.mroz)
modsumm<-summary(model.mroz)
print(modsumm)
print(str(modsumm))
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