Displaying 2 results from an estimated 2 matches for "starting_psi".
2012 Apr 02
7
Calculating NOEL using R and logistic regression - Toxicology
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]]
2012 Apr 03
0
Off Topic: Re: Calculating NOEL using R and logistic regression - Toxicology
...t; 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...