[R] density() returns a density function that does not add up to 1

Jonathan Li jonqli at labs.agilent.com
Fri Aug 30 21:50:28 CEST 2002

Dear R users,

I ran into this curious problem:

> d <- rnorm(100)
> d.density <- density(d)
> sum( d.density$x * d.density$y)
[1] 2.517502

Admittedly the method of computing the mass under the density curve at
line 3 is crude.
But 2.5 is pretty far from 1, the value it should be.

I tried a few other dataset and got similar result. Am I missing
something obvious?
Or is the return of density() not supposed to be normalized?

Thanks in advance!

Jonathan Q. Li, PhD
Agilent Technologies Laboratory
Palo Alto, California, USA
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