please refer to attachment

Problem 4. (9 points) To get the free COVlD-l9 test at the UM-Dearborn campus, you need to drive into the parking lot and wait in a queue. Also, you are informed by the county website that the expected waiting time before you get tested will be exponentially distributed with a cumulative density function as F (x) = 1 e'o'\" in minutes. a) So what is the average waiting time for you to get tested? b) What is the probability that you spend less than 4 minutes to get tested? (express the PMF formula and parameter values used clearly) c) What is the probability that you will wait more than the average wait time to get tested? (express the PMF formula and parameter values used clearly)