Rectangular Distribution (Uniform)
This continuous distribution is characterized by having the same probability for any value of the interval. It is widely used for contributions of type B uncertainties in which only the major and minor dimensions of the interval are known, for example in the division or resolution of a digital instrument. In many cases this distribution can also be assigned when there is little information about the random variable, in bibliographic data or when the coverage factor of an uncertainty is not known,
The general formula of this distribution is defined for all values of x for which A ≤ x ≤ B, according to the equation:
Input parameters:
- Average. Average value of the random variable.
- Semi-interval. Corresponds to the middle of the interval to which this distribution is applied, that is (B-A) / 2, where A and B are the upper and lower bounds of the interval. If this function is applied to the uncertainty by resolution of a digital instrument, this parameter will correspond to half of the minor division (d / 2). Sometimes it also applies to analogic instruments taking the appreciation (or estimation) as if it were an estimated division, beyond which it is no possible more visual information. In this case the semi-interval will be e / 2.
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