1. In a particular town, over a long period of time, it has been determined that police response time has a normal distribution with mean 8.4 minutes and a standard deviation of 1.7 minutes. What is the probability that for a randomly received emergency call, the response time will be less than 10 minutes?

a. Calculate the z-score that corresponds to 10 minutes.

b. What is the probability that a randomly received call would have a response time of more than 5 minutes?

c. Determine the proportion of calls that have a response time between 6 and 9 minutes.

d. How long does a response time need to be so that only 20% of response times are longer than that time?