maggiben

// derived from http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Parallel_algorithm

function map() {
    emit(1, // Or put a GROUP BY key here
         {sum: this.value, // the field you want stats for
          min: this.value,
          max: this.value,
          count:1,
          diff: 0, // M2,n:  sum((val-mean)^2)
    });

maggiben

/*

Copyright (c) 2006. All Rights reserved.

If you use this script, please email me and let me know, thanks!

Andrew Hedges
andrew (at) hedges (dot) name

If you want to hire me to write JavaScript for you, see my resume.