Dear Christian, it works great, and it is simple to understand, thank you very much.
just a detail, is it possible to plot just the fitted curve and not the data? it's because I would like to have data in black and the fitted curve in red.. I don't know how to pick up the single parts, if I simply wrote > plot(simone.m1, log="", col="red") everything became red.. thank in advance, Simone Il giorno 06/dic/07, alle ore 09:00, Christian Ritz ha scritto: > Dear Simone, > > you can use the package 'drc' to fit a logistic model, that is a non- > linear regression model based on the equation c+(d-c)/(1+exp(b(x- > e))), to your data (below named 'simone'): > > > ## Fitting a 4-parameter logistic model (also called Boltzmann model) > simone.m1 <- drm(size~x, data=simone, fct=B.4()) > > ## Plotting the data together with the fitted curve > plot(simone.m1, log="") > > > The fit is not great due to the bend. > > > Christian > ______________________________________________ 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.
