The algorithm comes from [*The Art of Computer Programing*, vol 2 by Knuth](http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#cite_note-5).

The algorithm comes from *The Art of Computer Programing*, vol 2 by [Knuth](http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#cite_note-5).

For documentation please refer to `ostat_test.go`.