Patients arrive for a physical examination according to a Poisson process at the rate 1 per hour. The physical examination requires three stages, each one independently exponentially distributed with a service time of 15 minutes. A patient must go through all the three stages before the next patient is admitted to the treatment facility. 1. What is the mean and variance of the total examination time? 2. Is the total examination time an exponential distribution? 3. Compute the average number of delayed patients, Lo for this system 4. Compute the total mean time a customer spends in the systenm ompute the average number of delayed patients, LQ for