Hi Ann As I read your code mode closely, I suspect that there could be another variables x1 and x2 somewhere in your search path which led to the error.
With fresh R session without any data this works as expected dold<-data.frame(x1=rnorm(10),x2=5*rnorm(10)) y<-1:10 predict(lm(y~x1+x2,dold),dn,se.fit=T) Cheers Petr On 16 Jul 2004 at 13:19, Petr Pikal wrote: > Hi > > On 16 Jul 2004 at 12:38, Anne wrote: > > > hello to all! > > > > 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 > > AFAIK predixt require to be fed by dataframe in which the > variables has the same names as was in lm() call. Either call lm() > with variables named "x1" and "x2" or build the dataframe "dn" with > names identical as are names in lm() call > > Cheers > Petr > > > > > > (I looked in the help and found the example > > > > x <- rnorm(15) > > y <- x + rnorm(15) > > new <- data.frame(x = seq(-3, 3, 0.5)) > > predict(lm(y ~ x), new, se.fit = TRUE) > > > > where is the difference?) > > > > > > Anne > > > > ---------------------------------------------------- > > Anne Piotet > > Tel: +41 79 359 83 32 (mobile) > > Email: [EMAIL PROTECTED] > > --------------------------------------------------- > > M-TD Modelling and Technology Development > > PSE-C > > CH-1015 Lausanne > > Switzerland > > Tel: +41 21 693 83 98 > > Fax: +41 21 646 41 33 > > -------------------------------------------------- > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > [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 > > Petr Pikal > [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 Petr Pikal [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
