[ https://issues.apache.org/jira/browse/MATH-704?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Thomas Neidhart updated MATH-704:
---------------------------------

    Attachment: MATH-704.patch

I have found a small bug wrt this bug report. The sum of the weights is calculated on the whole weight array rather than the specified sub-array [begin, begin + length)
                
> One of Variance.evaluate() methods does not work correctly
> ----------------------------------------------------------
>
>                 Key: MATH-704
>                 URL: https://issues.apache.org/jira/browse/MATH-704
>             Project: Commons Math
>          Issue Type: Bug
>    Affects Versions: 2.2
>         Environment: Java 1.6
>            Reporter: Leonid Ilyevsky
>            Assignee: Phil Steitz
>             Fix For: 3.0
>
>         Attachments: MATH-704.patch
>
>
> The method org.apache.commons.math.stat.descriptive.moment.Variance.evaluate(double[] values, double[] weights, double mean, int begin, int length) does not work properly. Looks loke it ignores the length parameter and grabs the whole dataset.
> Similar method in Mean class seems to work.
> I did not check other methods taking the part of the array; they may have the same problem.
> Workaround: I had to shrink my arrays and use the method without the length.

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