抄録
A calculation procedure which makes it possible to test any kind of dating data obtained by the grain by grain method is presented. The expected age frequency distribution for Mineral grains whose size and uranium content are variable can be calculated if the fission tracks counted are assumed to have Poisson distribution. The Chi-square test between the expected and the acutual age histograms provides the precision indexthat is defined to be a hundred times the upper probability integrals and ranges from 0 to 100.
