统计学中概率的一道题 求解

Question

The finance director of a hardwarewholesaler has asked the accountant to ring all customers five days beforetheir account payments are due, as a means of reducing the number of latepayments. As a result of time constraints, however, only 60% of customersreceive such a call from the accountant; 90% of the customers called pay ontime, while only 50% of those not called pay on time. The company has justreceived a payment on time from a customer. What is the probability that theaccountant called this customer?

Answer 1

你好这位同学，百度知道认证行家为你权威解答。

我们先来分析和理解一下这道题目。假设这个hardware wholesaler公司一共有100位客户。按照题目，其中有60人接到了accountant的电话，40人没有接到。

60-接到电话 = 54-按时交费[A] + 6-没有按时交费

40-没接到电话 = 20-按时交费[B] + 20-没有按时交费

现在题目告诉你，有一个客户按时交费了。那么这个客户要么是来自[A]，要么是来自[B]的。

因此，按时交费并且接到了电话的概率 = 54 / (54 + 20) = 0.73 或者按照百分比表示 73%

希望对你有帮助 :-)

Answer 2

P(ontime)=0.9*0.6+0.4*0.5=0.74

P(call)=0.6

P(ontime,call)=0,444