[Scipy-tickets] [SciPy] #1895: stats binom at non-integer n
SciPy Trac
scipy-tickets@scipy....
Tue Apr 23 11:00:10 CDT 2013
#1895: stats binom at non-integer n
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Reporter: josefpktd | Owner: rgommers
Type: defect | Status: new
Priority: normal | Milestone: Unscheduled
Component: scipy.stats | Version: 0.12.0
Keywords: |
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Comment(by josefpktd):
I completely agree, but what should be done
- just document it
- round ``n``
- check and return nans
Nobody has ever complained about this, and I only found it because of a
random check of the distribution.
Maybe the case where we run over a large number of n doesn't show up very
often (only in sample size calculations, and maybe estimation). So I guess
the check would cost much.
Floating point errors: what's the correct check? your BTW
I think I can convince myself to returning nans.
in R
{{{
> pbinom(3, 10.1, 0.5)
[1] NaN
> pbinom(3, 10., 0.5)
[1] 0.171875
> pbinom(3, 10.0000000001, 0.5)
[1] 0.171875
> pbinom(3, 10.000000001, 0.5)
[1] 0.171875
> pbinom(3, 10.00000001, 0.5)
[1] 0.171875
> pbinom(3, 10.0000001, 0.5)
[1] 0.171875
> pbinom(3, 10.000001, 0.5)
[1] NaN
}}}
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Ticket URL: <http://projects.scipy.org/scipy/ticket/1895#comment:4>
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