中文说明：
首先是针对无或单失效数据情形下，通过多层贝叶斯估计法得到失效概率过后，给出了寿命分布参数的加权最小二乘估计。然后如果失效数据不止一个，使用乘积限估计法来得到失效概率的估计值。
English Description：
Firstly, for the case of no or single failure data, the weighted least square estimation of life distribution parameters is given after the failure probability is obtained by multi-layer Bayesian estimation method. Then, if there is more than one failure data, the product limit estimation method is used to get the estimated value of failure probability.