Re: st: Average of Sample vesus Sub-Samples

[Jeph Herrin <junk@spandrel.net>]

Yes, if they are negative.


 A = -1,-1,-1
 B = -3
then
 mean(A) = -1
 mean(B) = -3
 (mean(A)+mean(B))/2 = -2
 mean(A+B)= -6/4 = -1.5

-1.5 > -2

So the average of all 4 numbers is larger than
the average of the means of the two subsamples.


hth,
Jeph





Erasmo Giambona wrote:
> Dear Statalisters,
>
> Is it possible that the arithmetic average of a sample is larger than
> the averages of two sub-samples containing overall all the
> observations of the full samples?
>
> Any thoughts would be appreciated,
>
> Erasmo
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