Thank and sorry i should check this before asking the question.

Andrija

On Thu, Dec 8, 2011 at 3:20 PM, R. Michael Weylandt <
michael.weylandt@gmail.com> <michael.weylandt@gmail.com> wrote:

> R FAQ 7.31 I'd imagine. (Floating point arithmetic and limitations thereof)
>
> Michael
>
> On Dec 8, 2011, at 9:15 AM, andrija djurovic <djandrija@gmail.com> wrote:
>
> > Hi all. I tried to calculate sum of deviations from the weighted mean
> and i
> > didn't get what i expected - 0. Here is an example:
> >
> >> wt <- c(10,25,38,22,5)
> >> x <- 6:10
> >> wm <- weighted.mean(x,wt)
> >> (x-wm)*wt
> > [1] -18.70 -21.75   4.94  24.86  10.65
> >> sum((x-wm)*wt)
> > [1] -1.24345e-14
> >
> > With simple mean I got 0:
> >> sum(x-mean(x))
> > [1] 0
> >
> > Could someone explain me why we didn't get 0, with weighted mean, as it
> is
> > expected?
> > Thanks in advance
> >
> > Andrija
> >
> >    [[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.
>

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