Deck 17: Supplement J Operations Scheduling

Question 1

Why is flow time an important measure of performance?

Answer 1

Minimizing job flow times in a schedule tends to minimize work-in-process inventory and maximize utilization. In addition, flow times are related to the lead times (or cycle times) of products and have an influence on customer service.

Question 2

Makespan is the time of completion of a group of jobs, plus the starting time of the first job.

Answer 2

False

Question 3

Which of the following statements on an operations schedule is best?

A) It determines when employees work.
B) It assigns employees to tasks depending on availability.
C) It assigns customers to a definite time for order fulfillment.
D) It assigns jobs to workstations or employees to jobs for specified time periods.

Answer 3

D

Question 4

Operations scheduling involves assigning jobs to workstations or employees to jobs for specific time periods.

Question 5

________ is the total amount of time required to complete a group of jobs.

Question 6

________ is the degree to which equipment, space, or the workforce is currently being used.

Question 7

________ scheduling assigns jobs to machines or employees to jobs.

Question 8

In the context of operations scheduling, total inventory is equal to:

A) scheduled receipts plus on-hand inventories.
B) received orders minus scheduled receipts.
C) on-hand inventories plus received orders.
D) None of these is equal to total inventory.

Question 9

Describe the difference between front office and back office operations from the standpoint of scheduling customer jobs.

Question 10

Operations scheduling applies only to manufacturing, because services do not allow inventories.

Question 11

The sum of scheduled receipts for all items and the on-hand inventories for all items is ________.

Question 12

The percent of work time productively spent by an employee or a machine is called:

A) activation.
B) efficiency.
C) effectiveness.
D) utilization.

Question 13

An appropriate objective for a manufacturing firm is to maximize total inventory.

Question 14

A job's flow time at a single workstation is defined as the:

A) completion time of the job plus the time since it arrived at the workstation.
B) processing time to complete the job.
C) time of completion of the last job of a group minus the starting time of the first job.
D) amount of time by which a group of jobs missed their due dates.

Question 15

In the context of operations scheduling, total inventory is the sum of the scheduled receipts for all items and the on-hand inventories for all items.

Question 16

A(n) ________ is the object receiving service or being manufactured.

Question 17

________ is the time a job spends in the service or manufacturing system.

Question 18

Utilization is the degree to which equipment, space, or the workforce is currently being used, measured as the ratio of average output rate to the maximum capacity.

Question 19

________ is the amount of time by which a job missed its due date.

Question 20

Makespan is the total amount of time to complete a single job or the first job in a group of jobs.

Question 21

When using the critical ratio (CR) priority sequencing rule:

A) a ratio of less than 1.0 implies that the job is ahead of schedule.
B) a ratio of less than 1.0 implies the job is behind schedule.
C) the job with the earliest due date is scheduled next.
D) the job with the highest CR is scheduled next.

Question 22

Table J.1
The framing department has six jobs waiting to be processed. It is now time zero. Times are expressed in terms of days.

Using the information in Table J.1 and the EDD rule, what is the average early time?

A) 0 days
B) greater than 0 but less than 1.5 days
C) greater than 2.5 but less than 2.5 days
D) greater than 2.5 days

Question 23

The fact that job shops routinely accept new orders at any time makes the scheduling environment dynamic.

Question 24

Which one of the following rules tends to perform well with respect to percentage of jobs past due and variance of hours past due, but performs relatively poorly with respect to average flow time?

A) earliest due date
B) shortest processing time
C) first-come, first-served
D) longest processing time

Question 25

Table J.1
The framing department has six jobs waiting to be processed. It is now time zero. Times are expressed in terms of days.

Using the information in Table J.1 and the EDD rule, what is the average flow time?

A) fewer than or equal to 25 days
B) greater than 25 days but fewer than or equal to 27 days
C) greater than 27 days but fewer than or equal to 29 days
D) greater than 29 days

Question 26

A manufacturer's flow shop utilizes line or continuous flow processes.

Question 27

A job shop is accompanied by divergent flows and low-to-medium volume output rates.

Question 28

Table J.1
The framing department has six jobs waiting to be processed. It is now time zero. Times are expressed in terms of days.

Using the information in Table J.1 and the SPT rule, what is the average flow time?

A) fewer than or equal to 19 days
B) greater than 19 days but fewer than or equal to 21 days
C) greater than 21 days but fewer than or equal to 23 days
D) greater than 23 days

Question 29

Table J.2
Stu Dent reviews the syllabi he received on the first day of class and pulls out his planner. He has seven major assignments that must be completed before the end of the semester.

What is the average flow time for all assignments scheduled in an SPT sequence?

A) 28.65
B) 32.14
C) 35.92
D) 36.88

Question 30

Slack is the difference between the time remaining until a job's due date and the total shop time remaining, excluding that of the operation being scheduled.

Question 31

When choosing a priority sequencing rule:

A) select multiple-dimension rules because they dominate single-dimension rules for all performance measures.
B) always select the rule that minimizes the amount of past-due jobs.
C) test a variety of rules before making a decision.
D) select CR or S/RO because they use more information.

Question 32

Critical ratio (CR) is a single-dimension priority rule.

Question 33

Sequencing jobs does not affect tardiness, because processing times are unchanged with different sequences.

Question 34

The earliest due date (EDD) rule gives the job with the shortest processing time the highest priority.

Question 35

A first-come, first-served schedule minimizes the average flow time for all jobs.

Question 36

Table J.2
Stu Dent reviews the syllabi he received on the first day of class and pulls out his planner. He has seven major assignments that must be completed before the end of the semester.

Develop an SPT sequence and calculate the average number of assignments Stu has this semester.

A) 3.36
B) 3.52
C) 3.78
D) 3.94

Question 37

Determining a production sequence for a group of jobs in a two-station flow shop to minimize the makespan has the advantage of:

A) maximizing the utilization of the shop.
B) minimizing the percentage of jobs past due.
C) minimizing the flow time of jobs on the first machine.
D) minimizing the variance of past-due hours.

Question 38

Table J.1
The framing department has six jobs waiting to be processed. It is now time zero. Times are expressed in terms of days.

Using the information in Table J.1 and the FCFS rule, what is the average flow time?

A) fewer than or equal to 19 days
B) greater than 19 days but fewer than or equal to 21 days
C) greater than 21 days but fewer than or equal to 23 days
D) greater than 23 days

Question 39

Table J.1
The framing department has six jobs waiting to be processed. It is now time zero. Times are expressed in terms of days.

Using the information in Table J.1 and the SPT rule, what is the average past due?

A) 0 days
B) greater than 0 days but fewer than or equal to 5 days
C) greater than 5 days but fewer than or equal to 10 days
D) greater than 10 days

Question 40

Table J.1
The framing department has six jobs waiting to be processed. It is now time zero. Times are expressed in terms of days.

Using the information in Table J.1 and the FCFS rule, what is the average past due?

A) 0 days
B) greater than 0 days but fewer than or equal to 5.5 days
C) greater than 5.5 days but fewer than or equal to 10 days
D) greater than 10 days

Question 41

Table J.7
The following four jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Using the information in Table J.7 and the S/RO rule, what is the average flow time at Workstation A?

A) fewer than or equal to 14.0 hours
B) greater than 14.0 but fewer than or equal to 14.5 hours
C) greater than 14.5 but fewer than or equal to 15.0 hours
D) greater than 15.0 hours

Question 42

Table J.5
The following three jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Use the information in Table J.5. The sequence of jobs using the slack per remaining operations (S/RO) rule, is:

A) 1-3-2
B) 3-2-1
C) 1-2-3
D) 2-3-1

Question 43

Table J.2
Stu Dent reviews the syllabi he received on the first day of class and pulls out his planner. He has seven major assignments that must be completed before the end of the semester.

What is the average flow time for all seven assignments if Stu schedules them using the critical ration criterion?

A) 38.17
B) 37.43
C) 36.67
D) 38.26

Question 44

Table J.2
Stu Dent reviews the syllabi he received on the first day of class and pulls out his planner. He has seven major assignments that must be completed before the end of the semester.

Stu decides to adopt an EDD sequence for the assignments, which seems like a very logical approach. Which assignments will he be submitting late?

A) C, D and F
B) B, C and F
C) B, E and G
D) F, E and G

Question 45

Table J.2
Stu Dent reviews the syllabi he received on the first day of class and pulls out his planner. He has seven major assignments that must be completed before the end of the semester.

Stu schedules his assignments using the critical ratio criterion. How many assignments are late?

A) 3
B) 4
C) 5
D) 6

Question 46

Table J.2
Stu Dent reviews the syllabi he received on the first day of class and pulls out his planner. He has seven major assignments that must be completed before the end of the semester.

Stu decides to adopt an SPT sequence for the assignments, which at face value seems like an odd choice. Which assignments will he be submitting late?

A) C, D and F
B) B, C and F
C) B, E and G
D) F, E and G

Question 47

Table J.6
All of the following three jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Use the information in Table J.6. What is the average flow time at Workstation A for the critical ratio rule?

A) fewer than or equal to 8 hours
B) greater than 8 hours but fewer than or equal to 9 hours
C) greater than 9 hours but fewer than or equal to 10 hours
D) greater than 10 hours

Question 48

Table J.5
The following three jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Use the information in Table J.5. The average past due using the slack per remaining operations (S/RO) rule is:

A) fewer than or equal to 9.0.
B) greater than 9.0 but fewer than or equal to 18.0.
C) greater than 18.0 but fewer than or equal to 27.0.
D) greater than 27.0.

Question 49

Table J.7
The following four jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Using the information in Table J.7 and the critical ratio (CR) rule, what is the job sequence?

A) C-D-B-A
B) D-C-B-A
C) A-C-D-B
D) D-B-A-C

Question 50

Table J.7
The following four jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Using the information in Table J.7 and the CR rule, what is the average flow time at workstation A?

A) fewer than or equal to 14.0 hours
B) greater than 14.0 but fewer than or equal to 14.5 hours
C) greater than 14.5 but fewer than or equal to 15.0 hours
D) greater than 15.0 hours

Question 51

Table J.5
The following three jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Use the information in Table J.5. The operations sequence of jobs, using the critical ratio (CR) rule, is

A) 3-1-2
B) 3-2-1
C) 1-2-3
D) 2-3-1

Question 52

Table J.8
Auto Data produces custom engineering testing equipment. The following six jobs are currently in the design department. The time since each one arrived, the processing time, and the due date are shown below. All times are expressed in terms of days. Let now be the beginning of Day 1.

Using the information in Table J.8 and the FCFS rule, what is the average days past due?

A) fewer than or equal to 5.0 days
B) greater than 5.0 days but fewer than or equal to 8.0 days
C) greater than 8.0 days but fewer than or equal to 9.0 days
D) greater than 9.0 days

Question 53

Table J.7
The following four jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Using the information in Table J.7 and the slack per remaining operations (S/RO) rule, what is the job sequence?

A) A-B-C-D
B) A-C-D-B
C) C-D-B-A
D) D-C-B-A

Question 54

Table J.5
The following three jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Use the information in Table J.5. The average past due using the ratio (CR) rule, is:

A) fewer than or equal to 9.0.
B) greater than 9.0 but fewer than or equal to 18.0.
C) greater than 18.0 but fewer than or equal to 27.0.
D) greater than 27.0.

Question 55

Table J.6
All of the following three jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Use the information in Table J.6. What is the job sequence at Workstation A, using the critical ratio rule?

A) 3-2-1
B) 1-2-3
C) 1-3-2
D) 2-1-3

Question 56

Table J.2
Stu Dent reviews the syllabi he received on the first day of class and pulls out his planner. He has seven major assignments that must be completed before the end of the semester.

Stu applies the critical ratio method to scheduling his assignments. Which assignment is the fourth one in his sequence?

A) E
B) G
C) C
D) D

Question 57

Table J.2
Stu Dent reviews the syllabi he received on the first day of class and pulls out his planner. He has seven major assignments that must be completed before the end of the semester.

Stu whips up a schedule based on the critical ratio criterion. What is the average number of assignments in the system?

A) 3.91
B) 3.71
C) 3.53
D) 3.14

Question 58

Table J.8
Auto Data produces custom engineering testing equipment. The following six jobs are currently in the design department. The time since each one arrived, the processing time, and the due date are shown below. All times are expressed in terms of days. Let now be the beginning of Day 1.

Using the information in Table J.8 and the SPT rule, what is the average days past due?

A) fewer than or equal to 6.0 days
B) greater than 6.0 days but fewer than or equal to 7.0 days
C) greater than 7.0 days but fewer than or equal to 8.0 days
D) greater than 8.0 days

Question 59

Table J.8
Auto Data produces custom engineering testing equipment. The following six jobs are currently in the design department. The time since each one arrived, the processing time, and the due date are shown below. All times are expressed in terms of days. Let now be the beginning of Day 1.

Using the information in Table J.8 and the EDD rule, what is the average days past due?

A) fewer than or equal to 8.0 days
B) greater than 8.0 days but fewer than or equal to 9.5 days
C) greater than 9.5 but fewer than or equal to 11.0 days
D) greater than 11.0 days

Question 60

Table J.6
All of the following three jobs just arrived (end of hour 0) at Workstation A. They are the only ones waiting to be processed.

Use the information in Table J.6. What is the average past due time at Workstation A for the critical ratio rule?

A) 0 hours
B) greater than 0 hours but fewer than or equal to 5 hours
C) greater than 5 hours but fewer than or equal to 10 hours
D) greater than 10 hours

Question 61

Table J.18

Use the information Table J.18 and sequence the jobs using the SPT rule. What is the average past due?

A) fewer than or equal to 29 hours
B) greater than 29 hours but fewer than or equal to 31 hours
C) greater than 31 hours but fewer than or equal to 33 hours
D) greater than 33 hours

Question 62

A(n) ________ specializes in medium- to high-volume production and uses line or continuous flow processes.

Question 63

Table J.11
Work center Q45 has four jobs that just arrived (the start of Day 1) to be processed, as shown in the following table. Assume the shop works eight hours per day.

Using the information in Table J.11 and the critical ratio rule, what should be the sequence of jobs processed at Q45?

A) A-B-C-D
B) D-A-C-B
C) D-C-B-A
D) B-C-A-D

Question 64

Table J.9
There are three jobs available for processing at Workstation 1. They just arrived at Workstation 1, at the end of Day 0.

Using the information in Table J.9 and the slack per remaining operation (S/RO) rule, what is the average days past due?

A) fewer than or equal to 6.0 days
B) greater than 6.0 days but fewer than or equal to 8.0 days
C) greater than 8.0 days but fewer than or equal to 9.0 days
D) greater than 9.0 days

Question 65

Table J.10
A workstation has six jobs waiting to be processed. They arrived at the end of Day 0 and it is now the beginning of Day 1. It is now time zero. Times are expressed in terms of days.

Using the information in Table J.10 and the earliest due date (EDD) rule, which job(s) will be completed on or before their due dates?

A) F only
B) A and F only
C) B, A, and E only
D) E and B only

Question 66

________ is a priority sequencing rule that determines priority by dividing the difference between the due date and today's date less the processing time remaining by the number of processing steps left to complete the job.

Question 67

Table J.9
There are three jobs available for processing at Workstation 1. They just arrived at Workstation 1, at the end of Day 0.

Using the information in Table J.9 and the slack per remaining operations (S/RO) rule, what should be the sequence of jobs processed at Workstation 1?

A) A-B-C
B) B-C-A
C) C-B-A
D) B-A-C

Question 68

Table J.18

Use the information in Table J.18 and sequence the jobs using the SPT rule. What is the average flow time?

A) fewer than or equal to 52 hours
B) greater than 52 hours but fewer than or equal to 54 hours
C) greater than 54 hours but fewer than or equal to 56 hours
D) greater than 56 hours

Question 69

Table J.11
Work center Q45 has four jobs that just arrived (the start of Day 1) to be processed, as shown in the following table. Assume the shop works eight hours per day.

Using the information in Table J.11 and the critical ratio rule, what is the flow time of job B?

A) fewer than or equal to 10 hours
B) greater than 10 hours but fewer than or equal to 20 hours
C) greater than 20 hours but fewer than or equal to 30 hours
D) greater than 30 hours

Question 70

A(n) ________ specializes in low- to medium-volume production using job or batch processes.

Question 71

Table J.8
Auto Data produces custom engineering testing equipment. The following six jobs are currently in the design department. The time since each one arrived, the processing time, and the due date are shown below. All times are expressed in terms of days. Let now be the beginning of Day 1.

Using the information in Table J.8, and either the FCFS, SPT or EDD rule, what is the fewest number of late jobs possible?

A) no late jobs
B) one late job
C) two late jobs
D) three late jobs

Question 72

Table J.18

Use the information in the table and sequence the jobs using the EDD rule. What is the average past due?

A) fewer than or equal to 32 hours
B) greater than 32 hours but fewer than or equal to 34 hours
C) greater than 34 hours but fewer than or equal to 36 hours
D) greater than 36 hours

Question 73

________ specify the job processing sequence when several jobs are waiting in line at a workstation.

Question 74

Table J.11
Work center Q45 has four jobs that just arrived (the start of Day 1) to be processed, as shown in the following table. Assume the shop works eight hours per day.

Using the information in Table J.11 and the shortest processing time (SPT) rule, what should be the sequence of jobs processed at Q45?

A) C-D-A-B
B) D-A-C-B
C) A-D-B-C
D) B-A-D-C

Question 75

Table J.18

Use the information in Table J.18 and sequence the jobs using the EDD rule. What is the average flow time?

A) fewer than or equal to 48 hours
B) greater than 48 hours but fewer than or equal to 50 hours
C) greater than 50 hours but fewer than or equal to 52 hours
D) greater than 52 hours

Question 76

Table J.9
There are three jobs available for processing at Workstation 1. They just arrived at Workstation 1, at the end of Day 0.

Using the information in Table J.9 and the critical ratio rule, what is the average flow time?

A) fewer than or equal to 9.0 days
B) greater than 9.0 days but fewer than or equal to 10.0 days
C) greater than 10.0 days but fewer than or equal to 11.0 days
D) greater than 11.0 days

Question 77

Table J.10
A workstation has six jobs waiting to be processed. They arrived at the end of Day 0 and it is now the beginning of Day 1. It is now time zero. Times are expressed in terms of days.

Using the information in Table J.10 and the earliest due date (EDD) rule, what is the average flow time?

A) fewer than or equal to 20 days
B) greater than 20 days but fewer than or equal to 22 days
C) greater than 22 days but fewer than or equal to 24 days
D) greater than 24 days

Question 78

Table J.11
Work center Q45 has four jobs that just arrived (the start of Day 1) to be processed, as shown in the following table. Assume the shop works eight hours per day.

Using the information in Table J.11 and the slack per remaining operations (S/RO) rule, what should be the sequence of jobs processed at Q45?

A) D-C-A-B
B) A-B-C-D
C) D-A-C-B
D) B-C-A-D

Question 79

Table J.9
There are three jobs available for processing at Workstation 1. They just arrived at Workstation 1, at the end of Day 0.

Using the information in Table J.9 and the critical ratio rule, what should be the sequence of jobs processed at Workstation 1?

A) C-B-A
B) B-A-C
C) A-B-C
D) B-C-A

Question 80

Table J.11
Work center Q45 has four jobs that just arrived (the start of Day 1) to be processed, as shown in the following table. Assume the shop works eight hours per day.

Using the information in Table J.11 and the slack per remaining operations ratio (S/RO) rule, what is the average past due?

A) fewer than or equal to 10 hours
B) greater than 10 hours but fewer than or equal to 20 hours
C) greater than 20 hours but fewer than or equal to 30 hours
D) greater than 30 hours