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# 问题

Questions in category: 概率论 (Probability).

## [Exer8-1] Exercise 75 of Book {Devore2017B} P.137

Posted by haifeng on 2020-04-07 08:01:38 last update 2020-04-07 08:01:38 | Answers (1) | 收藏

Suppose that the number of drivers who travel between a particular origin and destination during a designated time period has a Poisson distribution with parameter $\lambda=20$ (suggested in the article "Dynamic Ride Sharing: Theory and Practice", J. of Transp. Engr., 1997:308--312). What is the probability that the number of drivers will

• (a) Be at most $10$ ?
• (b) Exceed $20$ ?
• (c) Between $10$ and $20$, inclusive? Be strictly between $10$ and $20$ ?
• (d) Exceed the mean number by more than two standard deviations?