[SciPy-user] information on statistical functions
Wed Dec 17 20:03:27 CST 2008
On Wed, Dec 17, 2008 at 19:53, <firstname.lastname@example.org> wrote:
> On Wed, Dec 17, 2008 at 7:58 PM, Tim Michelsen
> <email@example.com> wrote:
>> I observed that there are 2 standard deviation functions in the
>> scipy/numpy modules:
>> What is the difference?
>> There is no formula included within the docstrings.
>> I suppose that np.std() is for the whole population and scipy.std is
>> designed for a smaller sample in the population.
>> Is that true?
> difference between population (numpy) and sample (scipy.stats)
> variance and standard deviation is whether the the estimator is
> biased, i.e. 1/n, or not, i.e. 1/(n-1).
It's a shame that the "biased/unbiased" terminology still survives in
the numpy.std() docstring. It's really quite wrong.
"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
-- Umberto Eco
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