[SciPy-user] information on statistical functions

josef.pktd@gmai... josef.pktd@gmai...
Fri Dec 19 12:09:59 CST 2008


On Thu, Dec 18, 2008 at 3:36 PM, Robert Kern <robert.kern@gmail.com> wrote:
> On Thu, Dec 18, 2008 at 09:43,  <josef.pktd@gmail.com> wrote:
>> I find the new doc string for np.var a bit misleading:
>>
>> "The mean is normally calculated as x.sum() / N, where N = len(x). If,
>> however, ddof is specified, the divisor N - ddof is used instead."
>>
>> This seems to refer to the divisor of the mean not of the variance.
>
> Yes, the "mean" as used in the variance formula given in the prior
> sentence. I don't really like the phrasing much, either, but I
> inherited it from what was already there.
>

The problem is that "mean" shows up twice in the previous sentence.

What about replacing mean in the sentence
"The mean is normally calculated as x.sum() / N, where N = len(x)."
by "average", which would unambiguously refer to the mean(average) of
the squared deviations in the previous sentence.

An english question: is divisor a synonym for denominator in common
use? When I looked it up in the dictionary it didn't seem to be the
case.

Josef


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