"The Poisson distribution applies when: (1) the event is something that can be counted in whole numbers; (2) occurrences are independent, so that one occurrence neither diminishes nor increases the chance of another; (3) the average frequency of occurrence for the time period in question is known; and (4) it is possible to count how many events have occurred, such as the number of times a firefly lights up in my garden in a given 5 seconds, some evening, but meaningless to ask how many such events have not occurred."
Dato che lavora sui numeri discreti è la statistica dei decadimenti radioattivi.
La pagina http://www.umass.edu/wsp/statistics/lessons/poisson/problems.html
propone proprio un problema che lavora sui dati del 1910
"Here are the classic 1910 observations of Rutherford, Geiger, and Bateman for the number of alpha particles emitted by a film of polonium, as observed over intervals of one-eighth of a minute (7.5 seconds). "
Here the answer