numericDeriv and ecdf

On only ten points, what did you expect ?  Even with 1000
observations, estimating a density is difficult, and has
been the subject of a century of research.  Kernel density
estimates are among the most successful.  For your immediate
application, try  plot(density(rnorm(10)), type="l"), etc.

-  tom blackwell  -  u michigan medical school  -  ann arbor  -

Hi All,

following expression:

  x <- sort(rnorm(10)); e <- ecdf(x); d <- numericDeriv(e(x),"x");

makes d far from approximation of one dimensional pdf.

What's wrong then here?

Kind regards.
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Valery A.Khamenya
Bioinformatics Department
BioVisioN AG, Hannover