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To: Joseph Syjuco <joseph@asti.dost.gov.ph>
Cc: postgres <pgsql-sql@postgresql.org>
Subject: Re: variance aggregate function incorrect? Reference Materials reg
	create aggregate
In-reply-to: <1024956806.2590.22.camel@Askr> 
References: <1024956806.2590.22.camel@Askr>
Comments: In-reply-to Joseph Syjuco <joseph@asti.dost.gov.ph>
	message dated "24 Jun 2002 18:13:25 -0400"
Date: Mon, 24 Jun 2002 11:39:25 -0400
Message-ID: <18525.1024933165@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Joseph Syjuco <joseph@asti.dost.gov.ph> writes:
> i needed the variance function ... i dont know if i introduced the wrong
> parameters or maybe this variance is not the variance that im looking
> for but it doesnt provide the right results

> variance=(nEx^2 - (Ex)^2)/(n(n-1))

That's what I'd expect it to do, all right.  Please define "doesnt
provide the right results".

			regards, tom lane