ExcelBanter

ExcelBanter (https://www.excelbanter.com/)
-   Excel Discussion (Misc queries) (https://www.excelbanter.com/excel-discussion-misc-queries/)
-   -   calculation of standard deviation is not as help document says (https://www.excelbanter.com/excel-discussion-misc-queries/92246-calculation-standard-deviation-not-help-document-says.html)

samemistake

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.

----------------
This post is a suggestion for Microsoft, and Microsoft responds to the
suggestions with the most votes. To vote for this suggestion, click the "I
Agree" button in the message pane. If you do not see the button, follow this
link to open the suggestion in the Microsoft Web-based Newsreader and then
click "I Agree" in the message pane.

http://www.microsoft.com/office/comm...lic.excel.misc

David Biddulph

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




All times are GMT +1. The time now is 12:24 AM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
ExcelBanter.com