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samemistake
 
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Default calculation of standard deviation is not as help document says

in the help manual of STDEV, it is said that the calculation uses the
"unbiased" formula, but in fact the actual calculation uses the biased one,
i.e. sqrt( sum(xi-xavg)/N), instead of the intended: sqrt(
sum(xi-xavg)/(N-1)).
am i right? if so, please correct the help document, to avoid the confusion.

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David Biddulph
 
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Default calculation of standard deviation is not as help document says

"samemistake" wrote in message
...
in the help manual of STDEV, it is said that the calculation uses the
"unbiased" formula, but in fact the actual calculation uses the biased
one,
i.e. sqrt( sum(xi-xavg)/N), instead of the intended: sqrt(
sum(xi-xavg)/(N-1)).
am i right? if so, please correct the help document, to avoid the
confusion.


No, You're wrong, I think.

It looks to me as if STDEV uses N-1 and STDEVP uses N, which is what the
help says. I'm using Excel 2003.

What numbers have you used to convince yourself that it's wrong? Which
version of Excel?
--
David Biddulph


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