Re: Idempotence and "Replication Insensitivity" are equivalent ?
From: Chris Smith <cdsmith_at_twu.net>
Date: Tue, 19 Sep 2006 12:40:40 -0600
Message-ID: <MPG.1f79e795d030d9ca989719_at_news.altopia.net>
Date: Tue, 19 Sep 2006 12:40:40 -0600
Message-ID: <MPG.1f79e795d030d9ca989719_at_news.altopia.net>
<pamelafluente_at_libero.it> wrote:
> this is an exaggeration. Everyone knows that the variance is simply
> the difference between the second moment and the square of the
> first moment. So you just need to accumulate values and their squares.
Ah. In that case, variance (and standard deviation) are efficient aggregate functions.
-- Chris SmithReceived on Tue Sep 19 2006 - 20:40:40 CEST