On Mon, 2007-09-07 at 10:39 -0400, Tom Lane wrote:
> When applied to "numeric" input, stddev_pop produces the same result as
> stddev_samp, and var_pop produces the same result as var_samp. This
> is because whoever wrote numeric_stddev_internal() forgot that the
> divisor is different for the sample case. This mistake is in fact
> visible in the regression test outputs for the function, so those
> outputs weren't checked very carefully :-(
My fault, I'm afraid -- how embarrassing! I certainly tested the
function for numeric inputs while developing it. I can only guess that I
wrote it and tested it, then refactored and broke it, and blindly copied
the resulting regression outputs => expected...
Sorry,
Neil