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.muggeo@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]]
> >
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> > and provide commented, minimal, self-contained, reproducible code.
>
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