Midterm 2

Gas stations, loading docks, and parking lots have infinite potential length of lines for their respective queuing systems. a. True b. False

b

You want to develop a three-sigma R-chart. You know the average range is 12 based on several samples of size 6. Which of the following is the resulting LCL? a. 20.0 b. 18.3 c. 7.02 d. 5.6 e. 0.0

e

For which of the following should we use a p-chart to monitor process quality? a. The dimensions of brick entering a kiln b. Lengths of boards cut in a mill c. The weight of fluid in a container d. Grades in a freshman "pass/fail" course e. Temperatures in a classroom

d

You have just used the capability index (Cpk) formulas to compute the two values "min [1, 1]." Which of the following is the proper interpretation of these numbers? rev: 03_24_2020_QC_CS-205448 a. The true capability index value is exactly 2. b. The mean of the production process has shifted to the left of the design limits. c. The mean of the production process has shifted to the right of the design limits. d. The mean has not shifted at all. e. None of these

d

You want to determine the control lines for a p-chart for quality control purposes. If the total number of defects from all samples is 2,500, the number of samples is 100, and the sample size is 50, which of the following would be the standard deviation used in developing the control lines? a. 0.4900 b. 0.2499 c. 0.1556 d. 0.0707 e. 0.02499

d

Arrival characteristics in a queuing problem analysis include the length of the queue. a. True b. False

b

Best customer last is a queue discipline discussed in the textbook. a. True b. False

b

A variable arrival rate is more common in waiting line management than a constant arrival rate. a. True b. False

a

An example of assignable variation in a production system may be that a machine is not adjusted properly. a. True b. False

a

An infinite population in waiting line management refers to a population that is large enough in relation to the service system so that the change in population size caused by subtractions or additions to the population does not significantly affect the system probabilities. a. True b. False

a

In a department 25 machines are kept running by three operators who respond to randomly occurring equipment problems. An analyst who wanted to know how much production was being lost by machines waiting for service could use queuing theory analysis to find out. a. True b. False

a

In acceptance sampling, the number of units in the sample (n) is determined by the interaction of the acceptable quality level (AQL), the lot tolerance percent defective (LTPD), the probability of rejecting a high-quality lot (alpha), and the probability of accepting a low-quality lot (beta). a. True b. False

a

In variables sampling, the actual measurements of the variable observed are used regardless of whether the unit is good or bad. a. True b. False

a

Quality control charts usually have a central line and upper and lower control limit lines. Which of the following is a reason that the process being monitored with the chart should be investigated? a. A single plot falls above or below the control limits. b. Behavior is normal. c. A large number of plots are on or near the central line. d. There is no real trend in any direction. e. There is a change in raw materials or operators.

a

Regardless of the computer language chosen for a simulation model, too much data from a simulation can be dysfunctional to problem solving. a. True b. False

a

Sampling plans are generally displayed graphically through the use of operating characteristic (OC) curves. a. True b. False

a

Statistical process control involves testing random samples of output from a process to determine whether the process is producing items within a preselected range. a. True b. False

a

The Poisson probability distribution is used in waiting line management when one is interested in the number of arrivals to a queue during some fixed time period. a. True b. False

a

The capability index (Cpk) indicates the position of the mean and tails of a process's variance relative to design specifications. a. True b. False

a

The central problem in virtually every waiting line situation is a decision balancing the costs of adding services with the costs of waiting. a. True b. False

a

The demand on a hospital's emergency medical services is considered an uncontrollable arrival pattern of the calling population. a. True b. False

a

The probability associated with rejecting a high-quality lot is denoted in acceptance sampling with the Greek letter alpha. a. True b. False

a

Variation that is inherent in a production process itself is called common variation. a. True b. False

a

Which of the following is an example of general-purpose simulation software? a. PC-MODEL b. MAP/1 c. SIMFACTORY d. Canella e. IVOPUS/2.3

a

Which of the following queue disciplines is discussed in the textbook? a. Emergencies first b. Garner-Whitten formula c. Newest customer first d. Patient customers last e. None of these

a

You are developing an X-bar chart based on sample means. You know the standard deviation of the sample means is 4, the desired confidence level is 99.7 percent, and the average of the sample means is 24. Which of the following is your UCL? a. 36 b. 24 c. 12 d. 4 e. None of these

a

You are going to develop an R-chart based on range statistics, and you are using a sample size of 15 for your charting purposes. Which of the following is the upper control limit D4 factor for the chart? a. 1.65 b. 1.70 c. 1.76 d. 1.87 e. 1.92

a

A p-chart has upper and lower control limits expressed as lines on the chart. As long as the sample values fall between these two lines, there is no need to investigate process behavior. a. True b. False

b

A tellers' window in a bank is an example of a single-channel, multiphase queuing system. a. True b. False

b

In modeling a simulation, random numbers from 00 to 99 are assigned with the intervals determined from frequency distributions for each behavior occurrence. Assume there are two behaviors, A and B, out of 100 tallies. On behavior A you record 45 tallies, and on behavior B you record 55 tallies. Which of the following is a correct random-number interval for behavior A? a. 00 to 45 b. 00 to 44 c. 56 to 99 d. 55 to 100 e. 45 to 100

b

LTPD in acceptance sampling stands for lot tolerance for parts defective. a. True b. False

b

One hundred percent inspection is justified when the cost of inspection is low. a. True b. False

b

Owners of a local restaurant are concerned about their ability to provide quality service as they continue to grow and attract more customers. They have collected data from Friday and Saturday nights, their busiest times of the week. During these time periods about 109 customers arrive per hour for service. Given number of tables and chairs, and the typical time it takes to serve a customer, the owners estimate they can serve on average about 100 customers per hour. Use Exhibit 4.6. During these nights, are they in the zone of service, the critical zone, or the zone of nonservice? a. Zone of service b. Zone of nonservice c. Critical zone

b

Process control is concerned with monitoring quality after the product or service has been produced. a. True b. False

b

Spreadsheet simulations have become obsolete due in part to specialized computer simulation languages like SLAM or SIMAN. a. True b. False

b

The Greek letter alpha is associated with consumer's risk. a. True b. False

b

The customer arrivals in a queuing system come almost exclusively from finite populations. a. True b. False

b

The customer arrivals in a queuing system come almost exclusively from infinite populations. a. True b. False

b

The term "queue discipline" involves the art of controlling surly and unruly customers who have become irritated by waiting. a. True b. False

b

Variation that is inherent in a production process itself is called assignable variation. a. True b. False

b

Which of the following is an example of a finite population in a queuing system? a. People waiting to place their order at a fast-food restaurant b. The departmental faculty in line at the copier c. People waiting in line at an ATM d. Patients seeking help in a hospital emergency room e. Taxpayers calling for assistance from the IRS

b

Assume the service rate for a queue in a truck-loading operation is 2 trucks per hour. Using the infinite queuing notion for the models presented in the textbook, which of the following is the average service time? a. 2 hours b. 1 hour c. 0.5 hour d. 0.25 hour e. None of these

c

Buying a ticket for a college football game where there are multiple windows at which to buy the ticket features which type of queuing system line structure? a. Single channel, single phase b. Single channel, multiphase c. Multichannel, single phase d. Multichannel, multiphase e. None of these

c

Buying food at a large food store with multiple checkout counters features which type of queuing system line structure? a. Single channel, single phase b. Single channel, multiphase c. Multichannel, single phase d. Multichannel, multiphase e. None of these

c

For which of the following should we use an R-chart to monitor process quality? a. Weighing trucks at a highway inspection station to determine if they are overloaded b. Deciding whether an airliner has sufficient fuel for its trip c. Student grades measured from 1 to 100 d. Determining whether vehicles from a motor pool will run e. Determining the accuracy of a forecast of "snow"

c

In modeling a simulation, random numbers from 00 to 99 are assigned with the intervals determined from frequency distributions for each behavior occurrence. Assume there are two behaviors, X and Y, out of 50 tallies. On behavior X you record 20 tallies, and on behavior Y you record 30 tallies. Which of the following is a correct random-number interval for behavior X? a. 00 to 19 b. 01 to 20 c. 00 to 39 d. 41 to 61 e. 45 to 100

c

What is the most commonly used priority rule for setting queue discipline, likely because it is seen as most fair? a. Last-come, first-served b. Priority queuing c. First-come, first-served d. Discriminate queuing e. Random queuing

c

Which of the following is a suggestion for managing queues that is mentioned in the textbook? a. Put up a serpentine lane to keep people from jumping ahead in line. b. Use humor to defuse a potentially irritating situation. c. Train your servers to be friendly. d. Assure customers that the wait is fair, and inform them of the queue discipline. e. Tell people in the queue that each will be served as soon as possible.

c

Which of the following is not a suggestion for managing queues presented in the textbook? a. Train your servers to be friendly. b. Segment the customers. c. Determine an acceptable waiting time for your customers. d. Inform your customers of what to expect. e. Encourage customers to come during slack periods.

c

You are going to develop an X-bar chart based on range statistics, and you are using a sample size of 12 for your charting purposes. Which of the following is the A2 factor for the X-bar chart? a. 0.37 b. 0.31 c. 0.27 d.0.22 e. 0.18

c

You have just used the capability index (Cpk) formulas to compute the two values "min [1.5, 1]." Which of the following is the interpretation of these numbers? a. The true capability index value is 1. b. The mean of the production process has shifted to the left of the design limits. c. The mean of the production process has shifted to the right of the design limits. d. The mean has not shifted at all. e. The true capability index value is between 1.5 and 1.

c

You want to determine the lower control line for a p-chart for quality control purposes. You take several samples of a size of 50 items in your production process. From the samples, you determine the fraction defective is 0.006 and the standard deviation is 0.001. If the desired confidence level is 99.7 percent, which of the following is the resulting LCL value for the line? a. 0.0 b. 0.002 c. 0.003 d. 0.004 e. None of these

c