Re: [R] small problem with predict

From: Petr Pikal <petr.pikal_at_precheza.cz>
Date: Fri 16 Jul 2004 - 21:19:10 EST


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
>
> ----------------------------------------------------
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> Email: anne.piotet@m-td.com
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Petr Pikal
petr.pikal@precheza.cz



R-help@stat.math.ethz.ch 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 Received on Fri Jul 16 21:37:48 2004

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