The government 311 hotline service is a nonemergency phone number that people can call in many U.S. and Canadian cities to find information about services, make complaints, or report problems like trash collection issues and potholes. Most cities perform analytics on call volumes to their call centers for purposes of maintaining adequate staffing and timely services. For the city of Chicago, the average number of 311 calls in the summer months is about 9.7 per hour for the night shift (11:00P.M. to 7:00A.M.). Suppose that the number of calls per time unit follows the Poissondistribution.

(Use decimal notation. Give your answers to two decimalplaces.)

Questions:

1. What is the average time between successive calls inminutes?

average time: ______________ minutes

2. Use software to find the probability that the time between successive calls is less than twominutes.

probability:

3. Use software to find the probability that the time between successive calls is greater than 15minutes. probability:

4. Use software to find the probability that the time between successive calls is between 55 and 10minutes. probability: