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Posted to notifications@accumulo.apache.org by "Mike Drob (JIRA)" <ji...@apache.org> on 2014/03/18 19:49:42 UTC

[jira] [Created] (ACCUMULO-2494) Stat calculation of STDEV may be inaccurate

Mike Drob created ACCUMULO-2494:
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             Summary: Stat calculation of STDEV may be inaccurate
                 Key: ACCUMULO-2494
                 URL: https://issues.apache.org/jira/browse/ACCUMULO-2494
             Project: Accumulo
          Issue Type: Bug
          Components: client
            Reporter: Mike Drob


The math is sound, but it is susceptible to rounding errors. We should address that.

See http://www.strchr.com/standard_deviation_in_one_pass and http://www.cs.berkeley.edu/~mhoemmen/cs194/Tutorials/variance.pdf



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