Mathematica: Strange no direct command to find Variance for population. Only for sample?
- From: "Nasser Abbasi" <nma@xxxxxxxxx>
- Date: Fri, 12 Oct 2007 19:24:51 -0700
Mathematica 6.0.
Doing help on Variance[], I do not see an option to tell it to obtain
Variance for population. (I think this is called Biased estimate).
i.e. I am looking for the definition of Var(x) using N in denominator not
N-1. The Variance command uses N-1, and no option to tell it to use N.
In Matlab for example, I do
EDU>> y=[1,2,3];
EDU>> var(y)
ans =
1
EDU>> var(y,1)
ans =
0.6667
The second case above is population variance (divide by N).
In Mathematica
In[12]:= y = {1, 2, 3};
Variance[y]
Out[12]= 1
I find it strange that no option exist to ask for populatio variance.
(ofcourse easy to do such a function, but I would think it should be part of
the Variance[] command allready)
Nasser
.
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