This reverts commit ea48370a500537906d62544ca4ed75301d79e772, reversing
changes made to 15939cb2d76c773950cda40988ede89e111872ea.
The commit was insufficiently tested and causes failures.
Change-Id: I623d6fc2cd3ae6fd42d0abab1f8eada465ae57a7
Always round sum error and sum square error toward zero in variance
calculations. This prevents variance from becoming negative.
Avoiding rounding variance at all might be better but would be far
more invasive.
Change-Id: Icf24e0e75ff94952fc026ba6a4d26adf8d373f1c
