Dear Ellison, You are right, now the figure is good! Question solved. Thank you very much! Best wishes, Luigi
-----Original Message----- From: S Ellison [mailto:[email protected]] Sent: 24 July 2012 10:20 To: Luigi; [email protected] Subject: RE: [R] limit of detection (LOD) by logistic regression > set 1; however the figure obtained from the sample set 2 > shows that interpolation is not correct. I don't think the interpolation is incorrect; what is making it look incorrect is using a straight line to represent a logistic regression. Try adding the predicted values for the line to your plot: lines( dil <- 10^seq(-1, 6, 0.05), predict(model, newdata=data.frame(dilution=dil), type="response")) S Ellison ******************************************************************* This email and any attachments are confidential. Any use...{{dropped:8}} ______________________________________________ [email protected] 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.
