Hi, I have been trying to figure out how to use the nonlinear regression to fit the cumulative lognormal distribution to a number of data points I have but I am a new R user and I cant quite decipher the notes on nonlinear regression. Any help in this regard will be greatly appreciated, my email address is mmiller at nassp.uct.ac.za
Is there some reason you don't want to use maximum likelihood? With the 2-parameter lognormal and no censored observations, the maximum likelihood estimates (MLEs) are just the mean and standard deviation of the logs. See ?fitdistr in library(MASS). If you really want nonlinear least squares, have you considered "nls"? In the likely event that this response does not meet your needs, I suggest you consider preparing another question using the posting guide! http://www.R-project.org/posting-guide.html, as it can increase the chances of getting a more helpful reply -- if you don't find an answer in the course of preparing a question following the guide. spencer graves Mark Miller wrote:> Hi, I have been trying to figure out how to use the nonlinear regression to > fit the cumulative lognormal distribution to a number of data points I have > but I am a new R user and I cant quite decipher the notes on nonlinear > regression. Any help in this regard will be greatly appreciated, my email > address is mmiller at nassp.uct.ac.za > > ______________________________________________ > R-help at 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-- Spencer Graves, PhD Senior Development Engineer PDF Solutions, Inc. 333 West San Carlos Street Suite 700 San Jose, CA 95110, USA spencer.graves at pdf.com www.pdf.com <http://www.pdf.com> Tel: 408-938-4420 Fax: 408-280-7915
Attached is a copy of my code, the data and the plots obtained by varying terms manually, I was told that nonlinear regression in R could find the values for me, but I am unable to figure how exactly I could implement this. Any help would be very greatly appreciated as I am completely stuck on this problem. On Thursday 04 August 2005 13:40, you wrote:> It might be good to have an example of your problem. > > On Aug 4, 2005, at 5:57 AM, Mark Miller wrote: > > Hi, I have been trying to figure out how to use the nonlinear > > regression to > > fit the cumulative lognormal distribution to a number of data > > points I have > > but I am a new R user and I cant quite decipher the notes on nonlinear > > regression. Any help in this regard will be greatly appreciated, > > my email > > address is mmiller at nassp.uct.ac.za > > > > ______________________________________________ > > R-help at 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-------------- next part -------------- A non-text attachment was scrubbed... Name: cumIAT.ps Type: application/postscript Size: 47024 bytes Desc: not available Url : https://stat.ethz.ch/pipermail/r-help/attachments/20050811/3e2bdc83/cumIAT.ps -------------- next part -------------- A non-text attachment was scrubbed... Name: cumTFR.ps Type: application/postscript Size: 13981 bytes Desc: not available Url : https://stat.ethz.ch/pipermail/r-help/attachments/20050811/3e2bdc83/cumTFR.ps -------------- next part -------------- A non-text attachment was scrubbed... Name: cumTTR.ps Type: application/postscript Size: 35507 bytes Desc: not available Url : https://stat.ethz.ch/pipermail/r-help/attachments/20050811/3e2bdc83/cumTTR.ps -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: Rstuff.R Url: https://stat.ethz.ch/pipermail/r-help/attachments/20050811/3e2bdc83/Rstuff.pl