Dear JC, > -----Original Message----- > From: Jean-Christophe BOUËTTÉ [mailto:jcboue...@gmail.com] > Sent: September-13-11 9:35 AM > To: John Fox > Cc: RCulloch; r-help@r-project.org > Subject: Re: [R] Force regression line to a 1:1 relationship > > And you can easily get these predictions using the following code : > A <- B
Indeed, which is why it's not clear to me that the model object is of real use. I suppose that it could be used for AIC(), anova(), etc. Best, John > > ;-) > JC > > 2011/9/13 John Fox <j...@mcmaster.ca>: > > Dear Ross, > > > > lm(y ~ 0 + offset(x)) will do the trick, but the resulting model has > > no coefficient estimates and thus can't be used with abline(). You > > can, e.g., get predictions from the model, but I'm not sure what real > > use it will be to you. > > > > I hope this helps, > > John > > > > -------------------------------- > > John Fox > > Senator William McMaster > > Professor of Social Statistics > > Department of Sociology > > McMaster University > > Hamilton, Ontario, Canada > > http://socserv.mcmaster.ca/jfox > > > > > > > >> -----Original Message----- > >> From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > >> project.org] On Behalf Of RCulloch > >> Sent: September-13-11 7:03 AM > >> To: r-help@r-project.org > >> Subject: [R] Force regression line to a 1:1 relationship > >> > >> Hello, > >> > >> I appreciate this is likely to be an easy question. I am trying to > >> obtain the residuals from a linear regression where the line is > >> forced to have a > >> 1:1 relationship. > >> > >> An example of the data: > >> > >> A<-c(0.9803922, 1.3850416, 0.8241758, 0.0000000, 0.4672897, > >> 1.1904762, 0.0000000, 0.9456265, > >> 1.5151515) > >> B<-c(1.3229572, 1.9471488, 1.3182674, 0.7007708, 1.0185740, > >> 1.0268562, 0.8695652, 0.3016591, 1.9667171) > >> > >> plot(A, B, ylim=c(0,2), xlim=c(0,2)) > >> abline(0,1, col="lightgrey", lty="dashed",lwd=2)#1:1 relationship = > >> what I want to use in the lm() > >> > >> #Normal regression > >> AB<-lm(A~B) > >> > >> #plot regression line > >> abline(lm(AB)) > >> > >> > >> How can I force the regression to have a 1:1 relationship, I assume > >> it is to do with offset() but I have somewhat fried my brain trying > >> numerous variations and I am not convinced any are correct. I was > >> also hoping the plot function would show me that the calculation is > >> correct, but any time I use the offset() command there is no line > plotted? > >> > >> Any hints or tips would be much appreciated! > >> > >> Ross > >> > >> > >> > >> -- > >> View this message in context: http://r.789695.n4.nabble.com/Force- > >> regression-line-to-a-1-1-relationship-tp3809733p3809733.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. > > > > ______________________________________________ > > 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.
