26. Patients arrive at a clinic with inter-arrival times that have an average and standard deviation equal to 8.33 and 4.17 minutes, respectively. The clinic has 4 doctors and the service time of each doctor has mean and standard deviation equal to 24 and 14 minutes, respectively. Patients form one line to go into any of the 4 doctor's offices. a) What is the coefficient of variation of the inter-arrival times? ( 4 pts) b) What is the average number of patients in the waiting room? ( 5pts) c) How many doctors are required to reduce the average patient waiting time to below 1 minute? (5 pts)