Close Approximations of Percentage Points of the Chi-Square Distribution and Poisson Confidence Limits
卡方分布分位点与泊松置信限的高精度近似
Two tables of modest size and three relatively simple formulas provide all that is required to obtain percentage points of the X2 distribution at 25 significance levels with relative accuracy of at least .99995; and to obtain Poisson confidence limits of such accuracy at 13 confidence levels. For a small number of degrees of freedom or observed number of events, where the formulas are weak, the tables give exact X2 values or Poisson limits.