Exam 22: Waiting Lines

A trucking firm has five trucks that each requires service at an average rate of once every 50 hours, according to an exponential distribution. The firm has a mechanic who needs five hours to complete the average job with exponential service times. -Use the information in Scenario C.5.What is the average utilization of the mechanic?

Customers arrive at the local grocery store at a steady rate of 40 an hour.Thirty percent of these customers purchase 10 items or less and go to the express line where they enjoy an average checkout time of 5 minutes.Customers that don't meet the express line criterion go to the other checkout line where they spend an average of 10 minutes checking out.How many people are checking out in the express line on average?

With a single-server model,increasing the promotions for a service through advertising will most likely

Weary travelers arrive at Will Rogers International Airport, pick up their luggage, stumble to their cars, and proceed to the parking lot attendant to pay for their parking. Traveler interarrival times are exponentially distributed, as are the service times of the attendant. On average, travelers arrive every 25 seconds. The attendant can process three travelers per minute. -Use the information in Scenario C.2.What is the average amount of time a customer spends waiting in line and being served?

A single ticket taker can tear tickets and direct movie patrons to their seats at a rate of 90 per hour. Customers arrive every minute 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. -Use the information in Scenario C.1.What is the average combined time a customer waits in line and spends being seated by the ticket taker?

The single,multiple,and finite queuing models all assume that

Weary travelers arrive at Will Rogers International Airport, pick up their luggage, stumble to their cars, and proceed to the parking lot attendant to pay for their parking. Traveler interarrival times are exponentially distributed, as are the service times of the attendant. On average, travelers arrive every 25 seconds. The attendant can process three travelers per minute. -Use the information in Scenario C.2.What is the probability that a traveler will pull up to the attendant's service window without having to wait for another customer?

In a waiting-line problem,assigning additional employees to a service facility will have a direct effect on

A single ticket taker can tear tickets and direct movie patrons to their seats at a rate of 90 per hour. Customers arrive every minute 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. -Use the information in Scenario C.1.What is the probability that customers with tickets arrive and the ticket taker is not helping another patron?

The average lead time of a unit of product through a manufacturing station is 10 minutes.The average work-in-process inventory at this station has been 30 pieces.What is the production rate?

If the nature of the customer population,constraints on the line,the priority rule,and the service time distribution renders waiting line theory no longer useful,then an operations manager should rely on

Customers arrive at the local grocery store at a steady rate of 40 an hour.Thirty percent of these customers purchase 10 items or less and go to the express line where they enjoy an average checkout time of 5 minutes.Customers that don't meet the express line criterion go to checkout line #2 where they spend an average of 10 minutes checking out.How many people are checking out in line #2 on average?

It is impossible for management to affect the rate of customer arrivals.

A trucking firm has five trucks that each requires service at an average rate of once every 50 hours, according to an exponential distribution. The firm has a mechanic who needs five hours to complete the average job with exponential service times. -Use the information in Scenario C.5.What is the average waiting time of trucks in line?

Pre-emptive discipline is a rule that allows a customer of lower priority to interrupt the service of another customer.

The mean of the Poisson distribution is equal to its standard deviation.

A bank that dedicates one window for commercial account customers and one window for personal account channel has two channels.

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?

With a finite-source model,increasing the arrival rate by 10 percent and also increasing the service rate by 10 percent will result in

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 C.6.What is the probability that there will be no tools in the system?