Re: Puzzled by the "Variance"
- To: mathgroup at smc.vnet.net
- Subject: [mg86548] Re: [mg86506] Puzzled by the "Variance"
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Thu, 13 Mar 2008 04:35:18 -0500 (EST)
- Reply-to: hanlonr at cox.net
As stated in the Help, Variance provides the unbiased estimate (divided by (Length[list] - 1) rather than Length[list]). See http : // mathworld.wolfram.com/Variance.html Bob Hanlon ---- 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?? > -- > Best Wishes! > Yours Sincerely > >