Thanks, that is interesting, but what I'm really after is an easy "no observed effect level", using a binomial logistic model ie glm. Have a great day!
On Mon, Apr 2, 2012 at 3:38 PM, vito.muggeo <vito.mug...@unipa.it> wrote: > dear Danielle, > > The NOEL is a threshold value or breakpoint in the range of dose. Have a > look to the > package segmented to estimate a GLM with unknown breakpoints. The code > (untested) should > be something like > > library(segmented) > o<-glm(y~1, family=binomial) > os<-segmented(o, ~dose, psi=starting_psi) > > Also the package segmented includes the dataset down that can be useful as > an example.. > > data(down) > with(down, plot(age, cases/births)) > > There is a paper of mine on R news 2008 discussing the package.. > > hope this helps you, > vito > > > > On Mon, 2 Apr 2012 14:45:06 -0800, Danielle Duncan wrote > > Hello, I used the glm function in R to fit a dose-response relationship > and > > then have been using dose.p to calculate the LC50, however I would like > to > > calculate the NOEL (no observed effect level), ie the lowest dose above > > which responses start occurring. Does anyone know how to do this? > > > > [[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. > > > -- > Open WebMail Project (http://openwebmail.org) > > [[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.
