Poissons Law
Poissons Law
This rule, which is also called Poisson’s Law of Small Numbers, is an elaboration of Bernouilli’s Theorem dealing with the difference between the actual and the most probable number of occurrences of an event. 1. In cases of Random Sampling, the Poisson Exponential Limit is used in place of the Normal Probability Function or the strict application of the Bernouilli Theorem, when considering events which happen rarely. 2. In cases of Dispersion of Statistical Ratios, a Bernouilli Distribution is used when the probability of an event is constant, and a Poisson Distribution is used when that probability is variable. In both cases, there is a maximum involved which will not be surpassed, and the values obtained by Poisson’s Law are smaller than those obtained in the other cases. — T.G.