Thank you, Barradas. It works when finding y, but when I tried to find x
using interpolation for a known y it gives 'NA' (for whatever y value). I
couldn't find out the reason. Any help is really appreciated.

Thanks,
Mano


On Thu, Oct 31, 2013 at 10:53 PM, Rui Barradas <ruipbarradas@sapo.pt> wrote:

> Hello,
>
> As for the problem of finding y given the ecdf and x, it's very easy, just
> use the ecdf:
>
> f <- ecdf(rnorm(100))
>
> x <- rnorm(10)
> y <- f(x)
>
> If you want to get the x corresponding to given y, use linear
> interpolation.
>
> inv_ecdf <- function(f){
>         x <- environment(f)$x
>         y <- environment(f)$y
>         approxfun(y, x)
> }
>
> g <- inv_ecdf(f)
> g(0.5)
>
>
> Hope this helps,
>
> Rui Barradas
>
> Em 31-10-2013 12:25, Manoranjan Muthusamy escreveu:
>
>> Hi R users,
>>
>> I am a new user, still learning basics of R. Is there anyway to extract y
>> (or x) value for a known x (or y) value from ecdf (empirical cumulative
>> distribution function) curve?
>>
>> Thanks in advance.
>> Mano.
>>
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