We would like to answer the comments by Dr. Matsubara and Dr. Ogata. According to their comments, we carried out additional statistical analyses that are shown below in detail. These additional analyses required no change in the results of our paper.

Our answers to each comment are as follows.

Tests on the normality of the distribution of life spans were carried out using the Kolmogorov-Smirnov method. The results showed that normality was not rejected in any of the groups except for the female 21-mGy/day group. Accordingly the shortening of the mean life span of the female 21-mGy/day group was tested by a non-parametric method (Mann-Whitney test), and the results were the same as those given in our paper.

We agree with the second comment about our statistical analysis. The Kaplan-Meier method (1) was applied to include the censored data (accidental deaths). Tests on the...

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