From telford@progsoc.uts.edu.au  Mon May 22 04:30:12 2000
From: telford@progsoc.uts.edu.au (Telford Tendys)
Date: Mon, 22 May 2000 13:30:12 +1000
Subject: [Rd] variance of a scalar (PR#546)
In-Reply-To: <200005190904.KAA22592@toucan.stats.ox.ac.uk>; from ripley@stats.ox.ac.uk on Fri, May 19, 2000 at 10:04:09AM +0100
References: <200005190904.KAA22592@toucan.stats.ox.ac.uk>
Message-ID: <20000522133012.C18391@ftoomsh.progsoc.uts.edu.au>

> > I thought that might be the reason.  There is no mention of using n-1
> > rather than n in the denominator on the help page.  Perhaps that might be
> > added?
> 
> Um. What professional statistics package uses n, then?  Are you
> suggesting that there is serious room for doubt?

I remember that my Casio calculator (in statistics mode) had some way
of setting the denominator to be n-1 or n so obviously someone at Casio
decided to cover both options. I was always taught to use n-1 but
I've been too lazy to work through the derivations and figure out why
one is better than the other.

I agree that a single sample cannot tell you anything about the variance
which is a good enough reason to convince me to keep using n-1.

	- Tel

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[Rd] variance of a scalar (PR#546)
Telford Tendys