And you can easily get these predictions using the following code : A <- B
;-) 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.
