On Sat, 19 Apr 2003 11:11:21 -0500, Bruno Wolff III <bruno@wolff.to>
wrote:
>stddev returns 0 when the number of rows is one. I would have expected null
>to be returned in this case as the standard deviation is undefined when
>there is one row.
As far as a little googling can tell, there a two kinds of standard
deviation: Depending on whether you are calculating the standard
deviation of the *whole population* or of a *sample* you divide by N
or by (N - 1), respectively, before you take the square root.
I'm not an expert, what I say here is from
http://www.beyondtechnology.com/tips016.shtml. Other web pages seem
to say the same. OpenOffice.org Calc has two flavours of standard
deviation, too.
Servus
Manfred