[R] problem with R. program

[S Ellison]

> After a run multdrc comment in R program, show warning sign in this
> program. I attached the saving page of the script. I hope you could help me,
> please.

Your model is probably generating negative or zero estimates, resulting in NaN when logs are taken.

But multdrc is no longer in drc. Suggest you update the package (current version is 3 or so) and use drm instead of multdrc. That is now tolerant off very small responses and simply running your model with drm gives (visually) a reasonably sensible-looking pair of curves.

Note that you probably no longer need to specify Upper limit and Lower limit, though I've not tried omitting them.

S Ellison



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