Hi Mario, in many applications there is not much difference between logistic and Gaussian distributions (just as logit and probit models often produce similar fits)...
Moreover it's possible to fit sigmoidal curves using models such as the (log-)logistic where the lower and/upper limits are estimated rather than fixed at 0 and 1, respectively. Have a look at the package 'drc' to see how! Also the following talk at the recent user! 2008 conference might be of interest to you: http://www.statistik.uni-dortmund.de/useR-2008//slides/Haubo.pdf Best wishes 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.
