Quiz 18: Management of Waiting Lines

Waiting lines occur even in underloaded systems because of variability in service rates and/or arrival rates.

A system has one service facility that can service 10 customers per hour. The customers arrive at a variable rate, which averages six per hour. Since there is excess capacity, no waiting lines will form.

The goal of waiting-line management is to eliminate customer waiting lines.

The cost of customer waiting is easy to estimate, the number waiting multiplied by the wait cost per minute.

In a theme park like Disney world, reservation systems are a win-lose situation since only those holding reservations are satisfied.

The point that minimizes total queuing system costs is that point where waiting costs and capacity costs are equal.

A multiple-channel system assumes that each server will have its own waiting line, and line changing is not permitted.

A dental office with two professionals (one dentist, one hygienist)who work together as a team would be an example of a multiple-channel system.

A single-server, variable-service-time system is known as an M/D/1 system.

The most commonly used queuing models assume that the arrival rate can be described by a Poisson distribution.

The goal of queuing analysis is to balance the cost of providing a level of service capacity with the possible loss of business due to customers leaving the line or refusing to wait.

According to Little's law, the number of people in line depends on the time of day that they arrive.

For a system that has a low utilization ratio, decreasing service capacity slightly will have only negligible effect on customer waiting time.

An approach to reducing the variability in processing times might include greater standardization.

The queuing models discussed in the text apply only to steady-state conditions. Steady state exists only when customers arrive at a steady rate; that is, without any variability.

In an infinite-source model, the average number being served is equal to the ratio of the arrival rate to the service rate.

In an infinite-source model, the average time in line is equal to the average number in line divided by the arrival rate.

In an infinite-source model, the system utilization is the ratio of the arrival rate to the service capacity.

To reduce the average number waiting in line, it is important to increase utilization.

All infinite-source queuing models require the system utilization to be less than 1.0.

Queue discipline requires a security presence to maintain order.

Compared to a single-channel system with exponential service time, a single-channel system with a constant service time causes a reduction of 50 percent in the average number waiting in line.

The value of standardizing some or all of a service is demonstrated by the shorter wait times observed in models with A)constant demand rates. B)finite queues. C)infinite sources. D)finite sources. E)constant service times.

Which of the following would tend to increase the difference between the actual time customers spent waiting and the perceived time spent waiting by those customers? (I)Lots of experience with the service on the part of customers(II)Anxiety on the part of customers(III)A pleasant physical environment for the customers A)I and II only B)I only C)II only D)III only E)I, II, and III

In which of these settings would one be least likely to encounter first-come service? A)a fast-food restaurant B)a doctor's office C)a hotel check-in operation D)an emergency room E)a check out line

A customer growing frustrated with the wait and leaving the facility (without being served)is an example of A)reneging. B)utilizing. C)balking. D)jockeying. E)departing.

Although it is generally the case that service systems have enough capacity, waiting lines result when __________ exceeds capacity for periods of time. A)homogeneity B)variability C)price D)demand E)heterogeneity

Why is there waiting in an infinite-source queuing system? A)poor scheduling of servers B)slow service C)low utilization D)variability in arrival and service rates E)multiple-phase processing

The goal of waiting-line management is to minimize A)the sum of customer waiting costs and capacity costs. B)the sum of customer waiting time and service time. C)capacity costs. D)customer waiting time. E)idle servers.

A basic difference between infinite-source and finite-source queuing models is the A)number of servers. B)average waiting time. C)arrival distribution. D)size of potential calling population. E)processing rate.

If a manager increases system utilization (assuming no change in the customer arrival rate)what happens to the customer waiting time? A)It increases exponentially. B)It increases proportionally. C)It decreases proportionally. D)It decreases exponentially. E)No change.

A single-phase queuing system is one which has a single A)channel. B)server. C)customer being served. D)operation. E)waiting line.

A single-channel queuing system has an average service time of eight minutes and an average time between arrivals of 10 minutes. The arrival rate is A)6 per hour. B)7.5 per hour. C)8 per hour. D)10 per hour. E)12.5 per hour.

In a _______ system, customers enter the waiting line, receive service, and leave. A)fast-track B)simulated C)queuing D)random E)non-random

Which of the following is not generally considered to be a measure of system performance in a queuing analysis? A)the average number waiting in line B)the average number in the system C)system utilization D)the cost of servers plus customer waiting cost E)average serving time

The total cost curve A)starts at zero and increases as service capacity increases. B)begins high and decreases as service capacity increases. C)starts high, declines, then increases again. D)remains relatively flat regardless of service capacity. E)starts at zero, increases rapidly, then declines slowly back to zero.

Little's law states that the average number of people in a waiting line is the average customer arrival rate multiplied by the A)average time in the system. B)average waiting time. C)service time minus the waiting time. D)average number in line. E)waiting time.

As the ratio of arrival rate to service rate is increased, which of the following is likely? A)Customers move through the system in less time because utilization is increased. B)Customers move through the system more slowly because utilization is increased. C)Utilization is decreased because of the added strain on the system. D)The average number in the system decreases. E)There really is no change since arrival rates are offset by service rates.

Each of the following is notation for a waiting-line model presented in the textbook except A)M/P/S. B)M/M/1. C)M/D/1. D)M/M/S.

A single-bay car wash with a Poisson arrival rate and an exponential service time has cars arriving an average of 10 minutes apart, and an average service time of four minutes. The system utilization is A).24. B).40. C).67. D)2.50. E)1.25.

A multiple-channel queuing system with a Poisson arrival rate and exponential service time has an average arrival rate of four customers per hour and an average service time of 18 minutes per customer. The minimum number of servers required to avoid an overloaded system is A)1. B)2. C)3. D)4. E)5.

Which one of the following measures of system performance is a key measure with respect to customer satisfaction? A)average number of customers waiting in line B)system utilization C)average number of customers in the calling population D)probability of a server being busy E)capacity costs per hour

A single-channel queuing system has an average service time of 16 minutes per customer, which is exponentially distributed. The manager is thinking of converting to a system with a constant service time of 16 minutes. The arrival rate will remain the same. The effect will be to A)increase utilization. B)decrease utilization. C)increase the average waiting time. D)decrease the average waiting time. E)not have any effect since the service time is unchanged.

When the waiting cost incurred likely varies based on some customer characteristic, an appropriate queuing model is A)single channel, single phase. B)single channel, multiple phase. C)multiple channel, single priority. D)multiple channel, multiple phase. E)multiple channel, multiple priority.

A ________ is one way of reducing perceived waiting time. A)bonus B)gatekeeper C)reservation D)diversion E)number calling system

An alternative strategy to increase the capacity of a service system is A)reducing the number of arrivals. B)increasing variability. C)increasing the processing rate. D)reducing the number of servers. E)reducing the processing rate.

A single-phase queuing system in which each arriving customer will be served by a three-member crew has four crews with three members each. The number of "servers" is A)3. B)4. C)7. D)12. E)1.

A multiple-channel system has customers arriving at an average rate of five per hour and an average service time of 40 minutes. The minimum number of servers for this system to be underloaded is A)2. B)3. C)4. D)5. E)6.

If a firm has reached the point at which further reducing waiting time is not economically feasible, reducing the ______________ is sometimes attractive. A)channels B)perceived service time C)capacity underload D)perceived waiting time E)system underutilization

A bank of 10 machines requires regular periodic service. Machine running time and service time are both exponential. Machines run for an average of 44 minutes between service requirements, and service time averages six minutes per machine. What is the probability that a machine will have to wait for service with two operators? A).654 B).090 C).346 D).910 E).016

A bank of 10 machines requires regular periodic service. Machine running time and service time are both exponential. Machines run for an average of 44 minutes between service requirements, and service time averages six minutes per machine. What is the average machine downtime with two operators? A).24. B)3.46 minutes C)6.25 minutes D)7.71 minutes E)9.46 minutes

A bank of 10 machines requires regular periodic service. Machine running time and service time are both exponential. Machines run for an average of 44 minutes between service requirements, and service time averages six minutes per machine. What is the average number of machines down when there is one operator? A)1.49 B)3.35 C)4.40 D)6.65 E)8.51

A bank of 10 machines requires regular periodic service. Machine running time and service time are both exponential. Machines run for an average of 44 minutes between service requirements, and service time averages six minutes per machine. If operators cost $15 per hour in wages and fringe benefits and machine downtime costs $75 per hour in lost production, what is the optimal number of operators for this bank of machines? A)1 B)2 C)3 D)4 E)5

A bank is designing a new branch office and needs to determine how much driveway space to allow for cars waiting for drive-up teller service. The drive-up service will have three tellers and a single waiting line. At another branch of the bank in a similar setting, the average service time for drive-up tellers is four minutes per customer, and average arrival rate is 36 customers per hour. It is expected that the new bank will have similar characteristics. How many spaces should be provided to have a 96 percent probability of accommodating all of the waiting cars? A)10 B)11 C)12 D)13 E)14

A restaurant at a popular Colorado casino provides priority service to player's card holders. The restaurant has 10 tables or booths where customers may be seated. The service time (time a booth or table is occupied)averages 42 minutes once a party is seated. The customer arrival rate is 8 parties per hour, with the parties being equally divided between card holders and people without player's cards. What is the average time that player's card holders wait to be seated? A)approx. 24 seconds B)approx. 55 seconds C)approx. 4 minutes D)approx. 40 minutes E)approx. 2 hours

A restaurant at a popular Colorado casino provides priority service to player's card holders. The restaurant has 10 tables or booths where customers may be seated. The service time (time a booth or table is occupied)averages 42 minutes once a party is seated. The customer arrival rate is 8 parties per hour, with the parties being equally divided between card holders and people without player's cards. What is the average time that parties without player's cards wait to be seated? A)approx. 24 seconds B)approx. 55 seconds C)approx. 4 minutes D)approx. 40 minutes E)approx. 2 hours

A restaurant at a popular Colorado casino provides priority service to player's card holders. The restaurant has 10 tables or booths where customers may be seated. The service time (time a booth or table is occupied)averages 42 minutes once a party is seated. The customer arrival rate is 8 parties per hour, with the parties being equally divided between card holders and people without player's cards. On average, how many parties with player's cards are waiting to be seated? A).000 B).027 C).061 D)2.827 E)5.688

A restaurant at a popular Colorado casino provides priority service to player's card holders. The restaurant has 10 tables or booths where customers may be seated. The service time (time a booth or table is occupied)averages 42 minutes once a party is seated. The customer arrival rate is 8 parties per hour, with the parties being equally divided between card holders and people without player's cards. On average, how many parties without player's cards are waiting to be seated? A).000 B).027 C).061 D)2.861 E)5.688

A restaurant at a popular Colorado casino provides priority service to player's card holders. The restaurant has 10 tables or booths where customers may be seated. The service time (time a booth or table is occupied)averages 42 minutes once a party is seated. The customer arrival rate is 8 parties per hour, with the parties being equally divided between card holders and people without player's cards. On average, how much longer do parties without player's cards spend in the system, compared to parties with the player's cards? A)approx. 30 seconds B)approx. 4 minutes C)approx. 8 minutes D)approx. 32 minutes E)It is impossible to say without more information.

Offering an "early bird" special at a restaurant to reduce waiting times during peak hours is an example of A)demand shifting. B)queuing psychology. C)service phasing. D)service standardization. E)outsourcing.

A restaurant that implements a limited menu and a "no substitutions" policy during peak dining hours is practicing _____________ with respect to waiting-line management. A)demand shifting B)queuing psychology C)service standardization D)service phasing E)outsourcing

Which of the following would reduce perceived waiting times most dramatically in a doctor's office? A)putting all clocks out of sight B)removing couches C)having the patient fill out forms D)implementing a "no-cell-phone" policy E)keeping expected waiting times from the patients

In a multichannel system with multiple waiting lines, customers shifting among the waiting lines is an example of A)departing. B)utilizing. C)abandoning. D)balking. E)jockeying.

This occurs when there is a temporary imbalance between supply and demand. A)reorders B)inventory mismanagement C)delays D)backorders E)waiting line

________________ is a mathematical approach to analyzing waiting lines. A)Chaos theory B)Matrix theory C)Coding theory D)Distribution theory E)Queuing theory

A multiple-server system has all the following assumptions except. A)Poisson arrival rate. B)exponential service time. C)first-come, first-served processing. D)customers form a single waiting line. E)servers all work at different rates

The design of a service system often is used by management to _____________ the cost of capacity in relation to the expected cost of customers waiting. A)eliminate B)zeroize C)maximize D)minimize E)balance

The optimal capacity is one that _____________ the sum of customer waiting costs and capacity or server costs. A)eliminates B)zeroizes C)maximizes D)minimizes E)balances