Thanks Jim. Yes it does... but I calculated the root mean square (rms), and
couldn't reproduce the result without multiplying the rms by 2. I don't know
why...

 > x=c(2,4,3,4,5)
> mean(x)
[1] 3.6
> x-mean(x)
[1] -1.6  0.4 -0.6  0.4  1.4
> scale(x)
           [,1]
[1,] -1.4032928
[2,]  0.3508232
[3,] -0.5262348
[4,]  0.3508232
[5,]  1.2278812
attr(,"scaled:center")
[1] 3.6
attr(,"scaled:scale")
[1] 1.140175
> rms=sum((x-mean(x))^2)^(1/2)/(length(x)-1)
> rms
[1] 0.5700877
> (x-mean(x))/rms
[1] -2.8065857  0.7016464 -1.0524696  0.7016464  2.4557625
> (x-mean(x))/(rms*2)
[1] -1.4032928  0.3508232 -0.5262348  0.3508232  1.2278812


On 1/3/08, jim holtman <jholtman@gmail.com> wrote:
>
> Does this give you what you want?
>
> > x=c(2,4,3,4,5)
> > ?scale
> > scale(x,scale=FALSE)
>     [,1]
> [1,] -1.6
> [2,]  0.4
> [3,] -0.6
> [4,]  0.4
> [5,]  1.4
> attr(,"scaled:center")
> [1] 3.6
> >
>
> Default is to performance scaling: "If scale is TRUE then scaling is
> done by dividing the (centered) columns of x by their
> root-mean-square, and if scale is FALSE, no scaling is done. "
>
> On Jan 3, 2008 9:37 PM, tom soyer <tom.soyer@gmail.com> wrote:
> > Hi,
> >
> > The documentation for scale() states:"If center is TRUE then centering
> is
> > done by subtracting the column means (omitting NAs) of x from their
> > corresponding columns". But it seems that R is subtracting something
> else
> > instead of the column mean:
> >
> > > x=c(2,4,3,4,5)
> > > mean(x)
> > [1] 3.6
> > > x-mean(x)
> > [1] -1.6  0.4 -0.6  0.4  1.4
> > > scale(x)
> >           [,1]
> > [1,] -1.4032928
> > [2,]  0.3508232
> > [3,] -0.5262348
> > [4,]  0.3508232
> > [5,]  1.2278812
> > attr(,"scaled:center")
> > [1] 3.6
> > attr(,"scaled:scale")
> > [1] 1.140175
> >
> > Notice that -1.4 is not the same as -1.6, and 1.2 is not the same as 1.4
> ,
> > etc. Does anyone know what exactly is scale() doing if it is not
> subtracting
> > the column mean? Thanks.
> >
> > --
> > Tom
> >
> >        [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > 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.
> >
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem you are trying to solve?
>



-- 
Tom

	[[alternative HTML version deleted]]


