1981 年 11 巻 2 号 p. 111-118
In this report we show that the left tail of a distribution for the waiting-time in an irreversible point process can be approximated fairly well by a gamma type distribution. Goodness of the approximation is exhibited by some numerical examples. The approximated formula will lead to versatile applica tion to data analysis in biological or medical study. An application of it to the quantification of carcinogenesis is illustrated.