Re: Standard deviation?


"Virgil" <Virgil@xxxxxxxxx> skrev i en meddelelse
news:Virgil-9EC47E.16001515052008@xxxxxxxxxxxxxxxxxxxxxxxxxxx
In article <g0i9oe$m3g$1@xxxxxxxxxxxxxxxxx>, "saneman" <asd@xxxxxx>
wrote:

I would like to calculate the standard deviation on this set of data:

v = 0.5677 0.4792 0.4844 0.4870 0.5104 0.4870 0.4792
0.4974 0.4688 0.4870

But how do I accomplish this without any information about the
propabilities?

I know of no formula for the standard deviation of a set of values that
involves an probabilities.


The standard deviation is the square root of the variance:

http://en.wikipedia.org/wiki/Variance

and the variance is formulated on the above link as the sum of the products
of with probabilities and the deviation. Thats why I thought it would be
necessary to now the probabilities too.


.

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