Talk:Statistics/Basic: Difference between revisions
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→stddev slightly wrong
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:::When talking about a set of sampled data, most frequently used is their [[wp:Mean|mean value]] and [[wp:Standard_deviation|standard deviation (stddev)]]. If you have set of data <math>x_i</math> where <math>i = 1, 2, \cdots n</math>, the mean is <math>\bar{x}\equiv {1\over n}\sum_i x_i</math>, while the stddev is <math>\sigma\equiv\sqrt{{1\over n}\sum_i \left(x_i - \bar x \right)^2}</math>.
::To me, this conveys that we are to supposed to use the population stddev on a set of sampled data. And for that matter, the use of random numbers implies that we are talking about samples. --[[User:Rdm|Rdm]] 21:49, 2 July 2011 (UTC)
== a bit of duplication ==
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