[R] small problem with predict

[Petr Pikal]

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: anne.piotet at m-td.com
> ---------------------------------------------------
> 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]]
> 
> ______________________________________________
> R-help at 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

Petr Pikal
petr.pikal at precheza.cz