You wrote: > I have a small problem wit predict() for lm > > Let's say I have predictors x1 and x2, response y > > I want to predict for a new ds say > dn<-data.frame(x1= seq(min(x1),max(x1),length=10),x2=rep(median(x2),10)) > > predict(lm(y~x1+x2),dn,se.fit=T) > > > Error message > > Error: variables 'x1', 'x2' were specified differently from the fit
I tried your example (with a made-up ``original'' x1 and x2, and y) and got a perfectly reasonable result, with no error message. Explicitly I did: > x1 <- runif(42) > x2 <- rnorm(42) > y <- 4 + 2*x1 + 3*x2 + rnorm(42) > dn <-data.frame(x1=seq(min(x1),max(x1),length=10), x2=rep(median(x2),10)) > predict(lm(y~x1+x2),dn,se.fit=T) No problema. Are you sure you did what you say you did? cheers, Rolf Turner [EMAIL PROTECTED] ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html