illumos/illumos-gate@79809f9cf479809f9cf4https://www.illumos.org/issues/8269
It seems that currently normalization of stddev aggregation is done
incorrectly.
We divide both the sum of values and the sum of their squares by the
normalization factor. But we should divide the sum of squares by the
normalization factor squared to scale the original values properly.
Reviewed by: Bryan Cantrill <bryan@joyent.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Andriy Gapon <avg@FreeBSD.org>
79edb7989a