Operations Management: Processes and Supply Chains, 12e (Krajewski)
Supplement H Measuring Output Rates
1) A work standard is the time required for a trained worker to perform a task following a prescribed
method with normal effort and skill.
2) The key to creating a work standard is defining normal performance.
3) The work measurement process creates labor standards based on the judgment of skilled observers.
4) Work standards would not be helpful for management in which area?
A) developing costs for current and new products
B) determining current and projected capacity requirements for a given demand
C) comparing different routings for an item and evaluating new work methods and equipment
D) forecasting demand for current products
5) A(n) ________ is the time required for a trained worker to perform a task following a prescribed
method with normal effort and skill.
6) The process of creating labor standards based on the judgment of skilled observers is ________.
7) Are time standards more useful for manufacturing or service processes? Why?
8) How can work standards be developed for higher level services and creative processes?
1) A time study is the method most often used for setting time standards for a job.
2) The select time is the average observed time based only on representative times.
3) A larger sample size is required when the job being studied is more consistent in completion time.
4) A larger sample size is required when the job being studied is shorter in average duration.
5) A larger sample size is required when the time estimate must be more certain.
6) The snap-back method of time study resets the stopwatch to zero on the completion of each work
element.
7) The standard time for a work element is found by multiplying the select time by a performance rating
factor.
8) The performance rating factor in a time study is a totally objective measure.
9) Fatigue, rest, or unavoidable delays are not factored into a work standard by the performance rating
factor.
10) Time studies are appropriate for setting time standards for tasks that are different each time.
11) The method used most often for setting time standards for a job is the:
A) elemental standard data approach.
B) time study method.
C) predetermined data approach.
D) work sampling method.
12) Timing the work elements using the snap-back method requires:
A) the worker to perform each job element as quickly as possible.
B) a larger sample size than using the continuous method.
C) the use of two stopwatches.
D) a smaller sample size than using the continuous method.
13) Garman observes a worker assembling peanut valves and records the data displayed in the table.
What is the select time for this job element?
Time (seconds)
Observations
20
15
25
12
30
12
A) 15 seconds
B) 20 seconds
C) 25 seconds
D) 30 seconds
14) Garman observes a worker assembling peanut valves and records the data displayed in the table.
During one of the cycles, the worker knocked the shaft out of the fixture and had to realign the fixtures.
What is the select time for this job element?
Time (seconds)
Observations
20
15
25
12
30
12
240
1
A) less than 23 seconds
B) greater than or equal to 23 seconds but less than 26 seconds
C) greater than or equal to 26 seconds but less than 29 seconds
D) greater than or equal to 29 seconds
15) Keith assembles peanut valves and the recorded data is displayed in the table. What is the select time
for this job element?
Time (minutes)
Observations
2.5
15
3.0
23
3.5
27
A) greater than or equal to 3 minutes
B) less than 3 minutes but greater than or equal to 2.7 minutes
C) less than 2.7 minutes but greater than or equal to 2.4 minutes
D) less than 2.4 minutes
16) Keith assembles peanut valves and the recorded data is displayed in the table. During one of the
cycles, he pauses to answer a phone call from his friend who suggests that he seek employment
elsewhere. Keith fields calls with some regularity, but that’s not considered part of his routine job
responsibilities. What is the select time for this job element?
Time (minutes)
Observations
2.5
15
3.0
23
3.5
25
10
1
A) greater than or equal to 3.2 minutes
B) less than 3.2 minutes but greater than or equal to 2.8 minutes
C) less than 2.8 minutes but greater than or equal to 2.4 minutes
D) less than 2.4 minutes
17) The gentleman farmer recorded the time it took to feed and water his chickens and collect eggs each
morning. He has done this several times, so he assigns himself a rating of 1.15. The allowance factor for
this endeavor is 5%. What is the select time for this job?
Observation
Time (min)
1
5
2
7
3
5
4
6
5
7
A) 5 minutes
B) 6 minutes
C) 7 minutes
D) 8 minutes
18) The gentleman farmer recorded the time it took to feed and water his chickens and collect eggs each
morning. He has done this several times, so he assigns himself a rating of 1.15. The allowance factor for
this endeavor is 5%. What is the normal time for this job element?
Observation
Time (min)
1
5
2
7
3
5
4
6
5
7
A) 6.3 minutes
B) 7.6 minutes
C) 6.9 minutes
D) 6.0 minutes
19) The gentleman farmer recorded the time it took to feed and water his chickens and collect eggs each
morning. He has done this several times, so he assigns himself a rating of 1.15. The allowance factor for
this endeavor is 5%. What is the standard time for this job element?
Observation
Time (min)
1
6
2
7
3
5
4
6
5
7
A) 6.0 minutes
B) 6.5 minutes
C) 6.9 minutes
D) 7.5 minutes
20) The gentleman farmer recorded the time it took to feed and water his chickens and collect eggs each
morning. He has done this several times, so he assigns himself a rating of 1.25. The allowance factor for
this endeavor is 5%. What is the standard time for this job element?
Observation
Time (min)
1
5
2
7
3
5
4
6
5
7
A) greater than or equal to 8.5 minutes
B) less than 8.5 minutes but greater than or equal to 8.0 minutes
C) less than 8.0 minutes but greater than or equal to 7.5 minutes
D) less than 7.5 minutes
21) Which one of the following statements about the time study method is true?
A) It is most appropriate for “thinking” jobs such as an automobile mechanic‘s diagnosis of a problem.
B) It is used most often for setting time standards.
C) Using the time study method technique, time standards can be set for new jobs before production
begins.
D) Performance ratings are not needed in the derivation of time standards.
22) A time study analyst is attempting to determine the standard time for a work element. She or he
observes a worker performing the work element at a lower-than-average pace. How will this fact be
reflected in the time standard that is eventually created?
A) The frequency of the work element per cycle will be increased.
B) The proportion of allowance time will be increased above 1.0.
C) The performance rating factor will be set less than 1.0.
D) The normal time for the work element will be increased.
23) To set a time standard for a machining operation, the least likely approach to be used is the:
A) time study method.
B) elemental standard data approach.
C) predetermined data approach.
D) work sampling method.
24) With a time study approach, the:
A) nature of the task can be different with each replication, and the standards will still be good.
B) skill of the observer is not very important.
C) sample size is a function of the desired precision of the time estimate.
D) sample size is typically larger than required for the work sampling approach.
25) When using a time study approach, the standard time is the:
A) normal time per cycle multiplied by 1.0 plus the allowance.
B) select time multiplied by the rating factor, summed over all work elements.
C) select time plus z times the standard deviation.
D) normal time plus z times the standard deviation.
26) An analyst using a time study approach:
A) observes the worker at random times, categorizing what he or she is doing at that time.
B) must rate the performance of the worker on each element of the total task.
C) divides the total task into micro-motions such as “reach” and “grasp” and then times the worker on
each one.
D) should use all observations in determining the standard, regardless of how irregular they might be, to
be fair to the worker.
27) During a time study, the following times were observed for a particular job using the continuous
(non-snapback) method: 22, 51, 72, 98, 128, and 150 seconds. There is only one element per cycle. The
sample standard deviation of the observed times has already been computed as 3.9 seconds. If an
estimate for the average time that is within 4 percent of the true long-range average 95 percent (z = 1.96)
of the time is desired, how many additional observations are needed?
A) fewer than or equal to 40
B) greater than 40 but fewer than or equal to 55
C) greater than 55 but fewer than or equal to 70
D) greater than 70
28) An industrial engineer is conducting a time study for a work element. The select time is 7.5 minutes,
and the sample standard deviation of the observed time is one minute. What is the appropriate sample
size if the estimate is to be 3 percent of the true average time 95 percent of the time (z = 1.96)?
A) fewer than or equal to 70
B) greater than 70 but fewer than or equal to 80
C) greater than 80 but fewer than or equal to 90
D) greater than 90
29) An industrial engineer is conducting a time study for a work element. The select time is 4.5 minutes,
and the sample standard deviation of the observed time is 20 seconds. What is the appropriate sample
size if the estimate is to be 5 percent of the true average time 95 percent of the time?
A) fewer than or equal to seven
B) greater than seven but fewer than or equal to eight
C) greater than eight but fewer than or equal to nine
D) greater than nine
30) A worker was observed for four cycles of a repetitive task. The observer used the continuous method
for recording the times. The continuous times (in seconds) for each element are:
Which one of the following are the “select times” ( ) for each element? The first number is the select time
for the first element, the second number is the select time for the second element, and so on.
A) 19.5, 23, 25, 30
B) 1.5, 3.5, 5, 2
C) 2, 3, 2, 5
D) 1.5, 3.5, 2, 5
31) A time study analyst is determining the standard time for a work element. The select time is 6.0
minutes, and the standard deviation of the select time is 2.2 minutes, based on a pilot sample of 20
observations. What is the appropriate sample size if the estimate for the select time is to be within 10
percent of the true average time 95 percent of the time (z = 1.96)?
A) fewer than 30 observations
B) greater than or equal to 30 observations but fewer than 40 observations
C) greater than or equal to 40 observations but fewer than or equal to 50 observations
D) greater than or equal to 50 observations
Table H.1
A worker was observed for four cycles in a repetitive task that contains four distinct elements. The
observer recorded the following items in seconds, using the snap-back method:
Element
Cycle 1
Cycle 2
Cycle 3
Cycle 4
Cycle 5
1
4
4
7
6
6
2
14
15
15
25
19
3
10
17
15
18
21
4
45
41
39
42
46
32) The observer assigned a performance rating factor of 1.05 to the worker and the company employs an
allowance factor of 15%. What is the select time for Element 1?
A) 5.4 seconds
B) 5.67 seconds
C) 6.52 seconds
D) 7 seconds
33) The observer assigned a performance rating factor of 1.10 to the worker and the company employs an
allowance factor of 15%. What is the normal time for Element 2?
A) 17.6 seconds
B) 19.36 seconds
C) 22.26 seconds
D) 24.78 seconds
34) The observer assigned a performance rating factor of 1.15 to the worker and the company employs an
allowance factor of 20%. What is the standard time for Element 3?
A) 16.2 seconds
B) 18.63 seconds
C) 22.36 seconds
D) 23.29 seconds
35) How many more observations must be made in order to estimate the select time for Element 1 if the
company wishes to be within 6% of the actual value with 95% confidence?
A) 81
B) 67
C) 53
D) 48
36) The observer assigned a performance rating factor of 1.15 to the worker and the company employs an
allowance factor of 20%. What is the select time for Element 2?
A) 25.3 seconds
B) 24.29 seconds
C) 20.24 seconds
D) 17.6 seconds
37) The observer assigned a performance rating factor of 1.15 to the worker and the company employs an
allowance factor of 20%. What is the normal time for Element 3?
A) 16.2 seconds
B) 23.29 seconds
C) 18.63 seconds
D) 22.36 seconds
38) The observer assigned a performance rating factor of 1.10 to the worker and the company employs an
allowance factor of 20%. What is the standard time for Element 4?
A) 58.58 seconds
B) 56.23 seconds
C) 46.86 seconds
D) 42.6 seconds
39) The observer assigned a performance rating factor of 1.15 to the worker and the company employs an
allowance factor of 20%. How many more observations must be made in order to develop an estimate of
the select time for Element 4 that is within 5% with 95% accuracy?
A) 1
B) 3
C) 5
D) 7
40) The observer assigned a performance rating factor of 1.15 to the worker and the company employs an
allowance factor of 20%. How many more observations must be made in order to develop an estimate of
the select time for all elements of the job that are within 3% with 95% accuracy?
A) 225
B) 357
C) 440
D) 429
Table H.2
Work Element
t (sec)
F
1
5.6
1
2
3.1
1
3
1.9
1
4
4.0
2
41) Use the information in Table H.2. Which work element will take the longest for an average worker to
perform per cycle?
A) work element 1
B) work element 2
C) work element 3
D) work element 4
42) Use the information in Table H.2. If the allowance for this task is 20 percent, what is the standard time
for the entire task?
A) fewer than 20 seconds
B) greater than or equal to 20 seconds but fewer than 22 seconds
C) greater than or equal to 22 seconds but fewer than 24 seconds
D) greater than 24 seconds
43) A time study analysis was performed on a task with two work elements. The select times for these
work elements are 21.0 seconds and 13.0 seconds, with rating factors of 1.1 and 1.2, respectively. Each
work element is performed twice per cycle. If an allowance of 20 percent is used, what is the standard
time for this task?
A) fewer than 50 seconds
B) greater than or equal to 50 seconds but fewer than 70 seconds
C) greater than or equal to 70 seconds but fewer than 90 seconds
D) greater than or equal to 90 seconds
44) If a worker spends 10 hours per day performing a task, and the allowance for this task is 19 percent,
how many hours during the average day is the worker involved in nonproductive activities?
A) fewer than 1.75
B) greater than or equal to 1.75 hours but fewer than 5 hours
C) greater than or equal to 5.00 hours but fewer than 8.25
D) greater than or equal to 8.25 hours
Table H.3
A worker was observed for four cycles in a repetitive task. The observer recorded the following times, in
seconds, using the continuous method. The ratings for each element and frequency it is performed are
also indicated in the table. The allowance fraction is 20 percent.
Element
Cycle 2
Cycle 4
Rating
Frequency
1
106
309
1.10
1.0
2
131
334
1.05
0.5
3
143
348
1.20
0.5
4
190
392
1.15
1.0
45) Use the information in Table H.3. What is the select time for work element 4?
A) fewer than 40 seconds
B) greater than or equal to 40 seconds but fewer than 60 seconds
C) greater than or equal to 60 seconds but fewer than or equal to 80 seconds
D) greater than or equal to 80 seconds
46) Use the information in Table H.3. What is the normal time for work element 2?
A) fewer than 10 seconds
B) greater than or equal to 10 seconds but fewer than 11 seconds
C) greater than or equal to 11 seconds but fewer than 12 seconds
D) greater than or equal to 12 seconds
47) Use the information in Table H.3. What is the standard time for work element 1?
A) fewer than 18 seconds
B) greater than or equal to 18 seconds but fewer than 20 seconds
C) greater than or equal to 20 seconds but fewer than 22 seconds
D) greater than or equal to 22 seconds
48) Use the information in Table H.3. What is the normal time for the complete cycle?
A) fewer than 85 seconds
B) greater than or equal to 85 seconds but fewer than 95 seconds
C) greater than or equal to 95 seconds but fewer than 105 seconds
D) greater than or equal to 105 seconds
49) Use the information in Table H.3. What is the standard time for the complete cycle?
A) fewer than 90 seconds
B) greater than or equal to 90 seconds but fewer than 97 seconds
C) greater than or equal to 97 seconds but fewer than 104 seconds
D) greater than or equal to 104 seconds
50) A time study analyst has found the select time for a work element to be 14.0 minutes, with a sample
standard deviation of 3.2 minutes. What is the minimum sample size needed if the estimate is to be
within 4 percent of the average 95 percent of the time (z = 1.96)?
A) fewer than 100
B) greater than or equal to 100 but fewer than 140
C) greater than or equal to 140 but fewer than 180
D) greater than or equal to 180