Question

各位大神，请问这道概率题怎么做啊？需要过程！ Refer to Exercise 3.122. I

各位大神，请问这道概率题怎么做啊？需要过程！
Refer to Exercise 3.122. If it takes approximately ten minutes to serve each customer, find
the mean and variance of the total service time for customers arriving during a 1-hour period.
(Assume that a sufficient number of servers are available so that no customer must wait for
service.) Is it likely that the total service time will exceed 2.5 hours?
3.122 ：Customers arrive at a checkout counter in a department store according to a Poisson distribution
at an average of seven per hour

Answer 1

mention和refer to区别的应用主要在于阅读题提问上

mention一般指上文中"提及"的内容

而refer to代表的意思比较多,常用的有"关于什么内容"或"推断出什么意思"...