Exam 19: Supplement B Waiting Lines

The production rate has been steady at 20 units per hour. The average work-in-process inventory at this station is 15 units. What is the average lead time through this manufacturing station?

A drive thru car wash can process cars at a rate of one every five minutes. The manager notices that during one particular day it takes cars an average of about 30 minutes in line to reach the car wash. What was the average number of cars in line on that day?

Scenario B.4 Customers arrive at an airline ticket counter at the rate of 50 customers per hour, according to a Poisson distribution. There are three ticket agents. Customers select the first available agent from one line. Each agent can process 20 customers per hour with exponential service times. -Use the information in Scenario B.4. What is the average time spent in the system?

The calling population in a queuing problem must go to the server, that is servers do not go to the calling population.

India Sisson wants to grab a latte before heading to her marketing class, knowing that the jolt of a double tall mocha is the only thing that can possibly keep her eyes open during today's presentation on the four P's. The server is slower than molasses in January and India notes that the pace of the line won't permit her to grab her favorite seat in the back row of her class. She decides to risk marketing without a latte and leaves the line before getting served. India's behavior is best described as:

A(n) ________ is a single step in providing a service.

An operations manager organizes a process improvement team and the resulting process has a lower mean (µ). Which statement is the best description of this change?

A harvesting firm has six combines, each requiring service at an average rate of once every 40 hours, according to an exponential distribution. The firm has a mechanic who needs four hours to complete the average repair with exponential service times. a. What is the average utilization of the mechanic? b. What is the average number of combines in the system? c. What is the average number of combines in line? d. What is the average time spent being repaired and waiting? e. What is the average time spent in line waiting for repair?

Students arrive at a university business library during peak evening hours at a rate of 40 students every half hour. A periodic count shows that there are 200 students in the library at any one time. On average, how long is each student's stay in the library?

Twelve customers arrive at the lunch counter at George's Happy Hog per hour and select the hickory smoked meat du jour along with a side and soda for $5. The server doubles as the cashier and can take and fill an order in three minutes on average. What is the likelihood that there are two customers in the system at the George's Happy Hog if the times can be assumed as exponentially distributed?

A(n) ________ is a rule that allows a customer of higher priority to interrupt the service of another customer.

Scenario B.6 The Jackson Machine Company has four cutting tools that need to be refurbished after an average of 30 hours, according to an exponential distribution. The single machine that refurbishes the tools needs 15 hours for each tool on the average, with exponential service times. -Use the information in Scenario B.6. What is the probability that there will be no tools in the system?

A Laundromat where there are washing machines and dryers is an example of a:

The average lead time of a unit of product through a manufacturing station is 18 minutes. The average work-in-process inventory at this station has been 30 pieces. What is the production rate?

Which statement about queue structure is best?

Scenario B.1 A single volunteer octogenarian usher can scan tickets with a handheld device and direct theater patrons to their seats at a rate of 30 per hour with an accuracy rate approaching 23%. On average, about twenty-five customers arrive every hour for assistance and always wait, regardless of how long the line gets. Arrivals are governed by the Poisson distribution and service is governed by the exponential distribution. -How busy is the octogenarian usher described in Scenario B.1?

With a single-server model, increasing the capital-to-labor ratio will most likely:

Customers in a small retail store arrive at the single cashier at the rate of 10 per hour. The average service time for the cashier is five minutes. Arrivals tend to follow a Poisson distribution, and service times follow an exponential distribution. a. What is the average utilization of the cashier? b. What is the average number of customers in the system? c. What is the average number of customers in line? d. What is the average time spent in the system? e. What is the average time spent in line?

Customers are serviced at a rate of five customers per hour according to an exponential distribution. What is the probability that customer service will require fewer than 20 minutes?

If the customer population of a service system generates customers according to a Poisson distribution, the exponential distribution describes the probability that the next customer will arrive in the next T time periods.