Question

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統計～
請問a.b小題要怎麼解🙏🙏

a.
4. The Boston Fire Department receives 911 calls at a mean rate of 1.6 calls per hour. Suppose the number
of calls per hour follows a Poisson probability distribution.
What is the probability that there will be less than one hour between 911 calls?
b. What is the probability that there will be 30 minutes or more between 911 calls?
c. What is the probability that there will be more than 5 minutes, but less than 20 minutes between 911
calls?