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Re: Puzzled by the "Variance"

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  • Subject: [mg86512] Re: Puzzled by the "Variance"
  • From: "Solomon, Joshua" <J.A.Solomon at>
  • Date: Thu, 13 Mar 2008 04:28:34 -0500 (EST)
  • References: <fr8b97$h2s$>

for sample variance, you want to divide by N-1, not N.

On 12/03/2008 10:28, in article fr8b97$h2s$1 at, "Elements"
<philyer at> wrote:

> Greeting all
> I'm puzzled by the function "Variance". We can learn how to calculate
> variance from this page:
> For example, calculate the sample variance of {1,2,3}. the average of
> {1,2,3} is 2, then the variance should be ((1-2)^2+(2-2)^2+(3-2)^2)/3=2/3.
> But mathematica gives that:
> In[10]:= Variance[{1.0,2.0,3.0}]
> Out[10]= 1.
> Why??

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