Note that you can do what you specified using only the rms package:
require(rms)
f <- Glm(propalive~exptime+infstat*status,
data=dat)
contrast(f,
a = list(status = levels(dat$status), infstat="control", exptime=8230),
b = list(status = levels(dat$status), infstat="infected",exptime=8230))
Frank
Joanne Lello wrote
>
> Dear all,
>
> I have been using the contrast library in my teaching for the last couple
> of years and am right in the middle of this year's round. In the last week
> R has been updated to version 2.14.0 on our computers. This has had the
> unfortunate effect of meaning the contrasts library no longer works, as
> the Design library is no longer available. I wonder if anyone has a fix
> for this...or alternatively can tell me another package that is as simple
> to use (the students won't cope with anything more complicated - we're all
> biologists not statisticians).
>
> I hope someone can help.
>
> Here is a typical bit of code I'm currently running so you can see what
> I'm trying to do:
>
> exptime is a covariate and both infstat and status are factors
>
> mod<-glm(propalive~exptime+infstat+status+
> infstat:status,
> data=dat)
>
> library(contrast)
>
> contrast(mod3,
> a = list(status = levels(dat$status), infstat="control", exptime=8230),
> b = list(status = levels(dat$status), infstat="infected",exptime=8230))
>
> any help gratefully received,
>
> Jo
>
> Dr Joanne Lello
> Cardiff University
> School of Biosciences
> Organism and Environment Group
> Biomedical Sciences Building
> Museum Avenue
> Cardiff
> CF10 3AX
> Tel: 02920 875885
> E-mail: lelloj@.ac
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@ 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.
>
-----
Frank Harrell
Department of Biostatistics, Vanderbilt University
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