Objective A convenient table for calculating 95% confidence interval of data with Poisson distribution was designed to estimate confidence interval of radiation biological dose.
Methods Based on the calculation methods of the cumulative probability sum of Poisson distribution, a method of calculating the confidence interval of variable X was established by using Excel function and iterative methods, and a 95% credible interval table was calculated by using the macro code loop. Then, an Excel application for estimating confidence interval of radiation biological dose was established based on this credible interval table, and finally the accuracy of this credible interval table and the estimated dose were verified.
Results A 95% confidence interval table with the parameters X ranged from 0 - 500 was successfully established by using the Excel methods, and the results were consistent with the confidence intervals given by authoritative textbooks. Compared with the results of the 95% confidence intervals of radiation biological dose by using normal approximation method and Poisson distribution table method, the difference was significant when aberrations number was small, while the difference was small when aberrations number was large. The 95% confidence interval based on the Poisson distribution table method was consistent with the results using the professional estimation software CABAS 2.0 recommended by the International Atomic Energy Agency (IAEA).
Conclusions The Excel method introduced in this article can be used to calculate the confidence interval of data with Poisson distribution and it is more reasonable to use this confidence interval table to estimate the 95% confidence interval of the biological radiation dose. Such convenient table can be used widely, and in particular can meet the needs of biological dose estimation in radiation emergency accidents.
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