Re: [Bug-gsl] Error in sample code

[Frantisek Kluknavsky]

On 02/26/2013 05:32 PM, Rhys Ulerich wrote:
> Hi Gerard,
>
> > Hello, I think there is a bug in "doc/examples/stat.out" (GSL 1.9).
> >
> > "The estimated variance is 4.2984" should be "The estimated variance is
> > 5.3730"
> Thank you for the report.  The latest version of the source does
> contain 5.3730 
> (http://bzr.savannah.gnu.org/lh/gsl/trunk/annotate/head:/doc/examples/stat.out).
>   Brian Gough corrected it back in 2010
> (http://bzr.savannah.gnu.org/lh/gsl/trunk/revision/4662).
>
> I think you are looking at an older version of GSL.  Version 1.9 is
> quite old.  The last public release is 1.15.
>
> Cheers,
> Rhys

Hi,

are you sure that "buggy" and correct behavior are not confused here? I 
do not know, but look at 
http://en.wikipedia.org/wiki/Bias_of_an_estimator and search for "usual 
definition of sample variance". If I understand it correctly, the 
"buggy" formula was unbiased, while now it is biased again.

Cheers,
Fero