A method to obtain the estimates for parameters and the size of fragile population and their confidence intervals in the trunsored and truncated models is introduced. When the censoring time becomes large, the width of the confidence interval for the size of fragile population in the trunsored model tends to a positive constant value, whereas that in the truncated model tends to zero.
A typical example of the method applied to the case fatality ratio of SARS shows different confidence intervals between the trunsored model and the truncated model.

壊れやすいサンプルと壊れにくいサンプルとが混合されたとき，壊れやすいサンプルの分布のパラメータとサンプル数の推定法を，trunsored modelとtruncated modelをそれぞれ用いて示している．打ち切り時間が長くなるとき，サンプル数の推定値の信頼区間の幅はtrunsored modelでは正の一定値に近づくが，truncated modelでは0に近づく．典型的な例としてSARSのケースを紹介している．