Kosár
The theoretical importance of Poisson distribution has lately come to be fully acknowledged with the development of theories on the sums of independent stoch- astic variables. Thanks to the works by such researchers as P. Lévy, W. FELLER and A. KHINTCHINE, the idea of indefinitely divisible probability laws has been introduced, and through this idea the true significance of Poisson distribution has been made quite clear in contrast with that of normal distribution-the fact, so to speak, that the former as well as the latter plays a basic rôle.
As to normal distribution we are provided with some precise tables, but, so far as the author knew in 1940, no sufficiently reliable tables for Poisson distribution were yet available with the only exception of Karl Pearson's table. For this reason the author felt not a little inconvenience when (in 1940) he began his investigations of applying Pólya-Eggenberger distribution to the statistical studies of rare events in seismology and epidemic diseases. The inconvenience the author felt then was such that he soon made up his mind to construct and publish more precise and complete tables for Poisson distribution in Japan....
