7.) To support National Heart Week, the Heart Association plans to install a free blood pressure testing booth in El Con Mall for the week. Previous experience indicates that, on the average, 10 persons per hour request a test. Assume arrivals are Poisson distributed from an infinite population. Blood pressure measurements can be made at a constant time of five minutes each. Assume the queue length can be infinite with FCFS discipline.
a.) What average number in line can be expected?
b.) What average number of persons can be expected to be in the system?
c.) What is the average amount of time that a person can expect to spend in line?
d.) On the average, how much time will it take to measure a person's blood pressure, including waiting time?
e.) On weekends, the arrival rate can be expected to increase to over 12 per hour. What effect will this have on the number in the waiting line?
8.) A cafeteria serving line has a coffee urn from which customers serve themselves. Arrivals at the urn follow a Poisson distribution at the rate of three per minute. In serving themselves, customers take about 15 seconds, exponentially distributed.
a.) How many customers would you expect to see on the average at the coffee urn?
b.) How long would you expect it to take to get a cup of coffee?
c.) What percentage of time is the urn being used?
d.) What is the probability that three or more people are in the cafeteria?
e.) If the cafeteria installs an automatic vendor that dispenses a cup of coffee at a constant time of 15 seconds, how does this change your answers to A and B?
24.) You are planning a bank, You plan for six tellers. Tellers take 15 minutes per customer with a standard deviation of 7 minutes. Customers arrive one every three minutes according to an exponential distribution (recall that the standard deviation is equal to the mean). Every customer that arrives eventually gets serviced.
a.) On average, how many customers would be waiting in line?
b.) On average, how long would a customer spend in the bank?
c.) If a customer arrived, saw the line, and decided not to get in line, that customer has ________?
d.) A customer who enters the line but decides to leave the line before getting service is said to have _________?