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) ______________________________________________ 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.
