I believe you are looking for the functionality I have in the norm.curve function in the HH package.
Download and install HH from CRAN and then look at example(norm.curve) ______________________________________________ R-help@stat.math.ethz.ch 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.