[R] Obtaining x-values from ECDF

David Winsemius dwinsemius at comcast.net
Sun Nov 18 23:19:54 CET 2007


That would give the x-values. He asked for the y-values at a particular x. 

 Instead he might try:

quantile(cawaocc$LEFF80, probs=0.8)

or

quantile(knots(Fn), probs=0.8)

-- 
David Winsemius

Henrique Dallazuanna wrote:
> try this:
>
> knots(cawa.cdp)
>
>   
On 18/11/2007, Benjamin Zuckerberg <bzuckerb at syr.edu> wrote:
> >
> > Dear Group,
> >
> > I am using the ecdf function as follows:
> >
> > cawa.cdp <- ecdf(cawaocc$LEFF80)
> >
> > summary(cawa.cdp)
> >
> > Empirical CDF:    223 unique values with summary
> >     Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
> > 0.07918 1.35700 1.68600 1.61000 1.91200 2.70000
> >
> > I can see by the summary that the y-value for the 3rd quartile is 1.912.
> >
> > How can I obtain the x-value for a specified y-value (e.g., 0.8)?



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