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Zhihong Yu commented on HBASE-5142: ----------------------------------- AggregationClient.std() already provides this capability. > Compute standard deviation using AggregateProtocol > -------------------------------------------------- > > Key: HBASE-5142 > URL: https://issues.apache.org/jira/browse/HBASE-5142 > Project: HBase > Issue Type: Sub-task > Reporter: Zhihong Yu > > Looking at http://en.wikipedia.org/wiki/Standard_deviation, I think two > passes are involved in computing std: > 1. compute average, u > 2. tuple of (sum of (xi-u)*(xi-u), number of rows) is returned from each > region > 3. client computes std based on results from step 2 -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira