Michael,

Thanks for the reply.  I believe Aline was sgiving me CI's on coefficients
as well.

So c(pred$fit + 1.96 * pred$se.fit, pred$fit - 1.96 *
pred$se.fit) gives me the CI on the logits if I understand correctly?  Maybe
the help on predict.glm can be updated.

Thanks!

On 6 August 2010 01:46, Michael Bedward <michael.bedw...@gmail.com> wrote:

> Sorry about earlier reply - didn't read your email properly (obviously :)
>
> You're suggestion was right, so as well as method for Aline below,
> another way of doing the same thing is:
>
> pred <- predict(y.glm, newdata= something, se.fit=TRUE)
> ci <- matrix( c(pred$fit + 1.96 * pred$se.fit, pred$fit - 1.96 *
> pred$se.fit), ncol=2 )
>
> lines( something, plogis( ci[,1] ) )
> lines( something, plogis( ci[,2] ) )
>
>
>
> On 6 August 2010 18:39, aline uwimana <rwan...@gmail.com> wrote:
> > Dear Troy,
> > use this commend, your will get IC95% and OR.
> >
> >  logistic.model <- glm(formula =y~ x1+x2, family = binomial)
> > summary(logistic.model)
> >
> > sum.coef<-summary(logistic.model)$coef
> >
> > est<-exp(sum.coef[,1])
> > upper.ci<-exp(sum.coef[,1]+1.96*sum.coef[,2])
> > lower.ci<-exp(sum.coef[,1]-1.96*sum.coef[,2])
> >
> > cbind(est,upper.ci,lower.ci)
> >
> > regards.
> >
> > 2010/8/6 Troy S <troysocks-tw...@yahoo.com>
> >
> >> Dear UseRs,
> >>
> >> I have fitted a logistic regression using glm and want a 95% confidence
> >> interval on a response probability.  Can I use
> >>
> >> predict(model, newdata, se.fit=T)
> >>
> >> Will fit +/- 1.96se give me a 95% of the logit?  And then
> >> exp(fit +/- 1.96se) / (exp(fit +/- 1.96se) +1) to get the probabilities?
> >>
> >> Troy
> >>
> >>        [[alternative HTML version deleted]]
> >>
> >> ______________________________________________
> >> R-help@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.
> >>
> >
> >        [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@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.
> >
>

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