Abstract
The authors have studied phenomenon of indoor seismic casualty from a probabilistic standpoint. The purpose of this paper is to unveil a relationship of estimation formulas for seismic casualty between an actual model using hypergeometric distribution and an approximate model using binomial distribution. The problem is solved comparing the differences of probability values between the two models to human density calculated the number of human per the floor space. As a result, it was found that the differences are extremely small under most indoor spaces including residences. In conclusion, the approximate model using binomial distribution has high usability compared with the actual model using hypergeometric distribution.
