Re: Puzzled by the "Variance"
- To: mathgroup at smc.vnet.net
- Subject: [mg86512] Re: Puzzled by the "Variance"
- From: "Solomon, Joshua" <J.A.Solomon at city.ac.uk>
- Date: Thu, 13 Mar 2008 04:28:34 -0500 (EST)
- References: <fr8b97$h2s$1@smc.vnet.net>
for sample variance, you want to divide by N-1, not N. j On 12/03/2008 10:28, in article fr8b97$h2s$1 at smc.vnet.net, "Elements" <philyer at gmail.com> wrote: > Greeting all > I'm puzzled by the function "Variance". We can learn how to calculate > variance from this page:http://mathworld.wolfram.com/SampleVariance.html. > 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??