That's not the way to use logistic regression. See http://stats.stackexchange.com/questions/14803/graphically-presenting-model-fits-of-logistic-regression for some other ideas. Frank
Weidong Gu-2 wrote: > > Andra, > > You can transfer the probabilities into class membership by setting up > a cut-off value, usually 0.5. > > set.seed(3) > x<-rnorm(100) > y<-rbinom(100,prob=1/(1+exp(x)),size=1) > model<-glm(y~x,family=binomial(link=logit)) > pred<-ifelse(predict(model,type='response')>0.5,1,0) > table(pred,y) > > > Weidong Gu > > On Fri, Aug 26, 2011 at 12:58 AM, Andra Isan <andra_i...@yahoo.com> > wrote: >> Hi All, >> >> When modeling with glm and family = binomial (link = logit) and response >> values of 0 and 1, I get the predicted probabilities of assigning to my >> class one, then I would like to compare it with my vector y which does >> have the original labels. How should I change the probabilities into >> values of zero and 1 and then compare it with my vector y to find out >> about the accuracy of my prediction? >> >> Thanks, >> Andra >> >> ______________________________________________ >> 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. >> > > ______________________________________________ > 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. > ----- Frank Harrell Department of Biostatistics, Vanderbilt University -- View this message in context: http://r.789695.n4.nabble.com/How-to-find-the-accuracy-of-the-predicted-glm-model-with-family-binomial-link-logit-tp3770027p3770932.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
