2. Specific laws used in estimates

2.1 Central limit theorem

Particularly important in practice, this theorem, which in reality admits several neighbouring, slightly different forms, legitimately allows a large number of distributions to be reduced to Gauss's law. We propose here to give various forms, without demonstration.

• Let {X _n }, n = 1,2,..., be a sequence of independent random variables with the same distribution, mean value m and standard deviation σ. The sequence {Y _n }, n = 1,2,..., of random variables defined by : $Y_n=\frac{X_1+X_2+\dots +X_n-nm}{\sigma \sqrt{n}}$

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