Abstract: The four properties and the fundamental model of Bayes’s formula and the importance of solving problems were stated in risk decision. Two typical cases were enumerated, and they illustrated the effectiveness and good results of Bayes theorem in the application process|the drawing and operation process of decision tree method were explained in detail.

Key words: Bayes theorem, Risk type decision, Prior probability, Posterior probability, Expected value

摘要： 阐述了风险型决策的4个特性、 贝叶斯定理公式的基本模型及其对解决风险型决策问题的重要意义。
重点列举两个典型案例, 生动具体地说明了贝叶斯定理在风险型决策中的应用过程以及产生的良好效应, 同时对决
策树方法进行了规范并进行了详细的讲解。

关键词: 贝叶斯定理, 风险型决策, 先验概率, 后验概率, 期望值