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From: "Ulrik Nash" <uwn@sam.sdu.dk>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Finding variance of vector, discounting zeros.
Date: Thu, 10 Nov 2011 18:34:27 +0000 (UTC)
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"Nasser M. Abbasi" <nma@12000.org> wrote in message <j4vqip$2ar$1@speranza.aioe.org>...
> On 9/16/2011 8:23 AM, Ulrik Nash wrote:
> > Suppose I have a column vector, which includes zeros. How do I find the variance
> >of all the numbers, discounting the zeros?
> >
> > Regards,
> >
> > Ulrik.
> 
> i am not good in statistics, but how about simply finding the variance
> of all non-zero elements in the vector?
> 
> 
> v=[1 2 3 0 4 0 8];
> 
> EDU>> var(v(v~=0))
> 
> ans =
> 
>      7.3000
> 
> --Nasser


Suppose that I instead wish to calculate the variance of each column in a matrix, still disregarding zeros, how can I do that without the toolbox?