Abstract
Bayesian approach becomes widely spread over the verious fields of statistical applications of sciences and engineering in the computer intensive manner. No exception will be frequency analysis for heavy rains in hydorological engineering. The preliminary survey is neccessary in the theoretical sense of the intrinsic property of extremes. Extrapolation in extreme value analysis can be conducted in two paths: one is an externally equipped path, the other is a path enclosed in the same footing with the observed data. The latter path is rational but actually the former is employed in practice. The same goal should be achieved essentially in both paths. The agreement and disagreement are demonstrated in the numerical sense.
