how to interpolate a plot with a logistic curve
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