Test Bank Ch.8s Supplement 8 Work Measurement 4e Rieger

Supplement 8:
Operational Decision-Making Tools: Work Measurement

True/False

1. Determining the length of time it takes to do a job is known as
   1. standard time.
   2. learning curve.
   3. work measurement.
   4. cycle time.
2. The historical objective behind work measurements and time studies was to
   1. develop a fair method of job evaluation and payment.
   2. provide an aspect of control over workers.
   3. provide motivation for work.
   4. increase quality improvements.
3. Under normal circumstances and conditions, the time required by an average worker to perform a job once is referred to as the
   1. standard.
   2. cycle time.
   3. normal elemental time
   4. time study.
4. The basic principle underlying an incentive piece-rate wage system is that
   1. management pays more for more work.
   2. workers make money for more work.
   3. allows for easy determination of a normal or fair rate of output.
   4. workers produce more if they are paid for the additional output.
5. The normal time to perform a job is calculated by
   1. dividing the standard time by the elemental average.
   2. dividing the elemental average by the standard time.
   3. summing the elemental normal times.
   4. None of the answer choices are correct.
6. The allowance factor is a
   1. reduction in the standard time.
   2. percentage increase in the normal cycle time.
   3. a component of normal time.
   4. a component of average time.
7. A ______ is a statistical sample distribution, where the number of cycles is the sample size.
   1. motion time
   2. work sampling
   3. time study
   4. average cycle time
8. Which of the following is a negative aspect to time studies?
   1. Workers often do not like to be the subject of a time study.
   2. They are costly to conduct.
   3. Workers are sometimes unwilling to cooperate.
   4. All of the answer choices are correct.
9. Rating worker performance is typically an objective, easy task that can be done by any employee.

Difficulty: Easy

1. Work sampling is best defined as
   1. a technique for determining the proportion of time a worker or machine is idle.
   2. a technique for determining the proportion of time a worker spends on activities.
   3. a technique for determining the elemental normal times.
   4. a technique for breaking a job down into its elements.
2. Which of the following is NOT a benefit of work sampling as compared to time studies?
   1. easier to perform
   2. cheaper
   3. large number of observations
   4. no stopwatch used
3. Work sampling tends to be more disruptive on the workplace than time studies.

Difficulty: Moderate

Multiple Choice

1. _____________ time is the time required by an average worker to perform a job under normal circumstances and conditions.
2. Stopwatch
3. Standard
4. Allowance
5. Average

Difficulty: Moderate

1. In a time study, the normal time is computed as
2. the elemental average time multiplied by the rating factor.
3. the elemental average time divided by the rating factor.
4. the elemental average time minus the rating factor.
5. the elemental average time plus the rating factor.

Difficulty: Hard

1. In a time study the standard time is calculated as
2. the normal cycle time plus the allowance factor.
3. the normal cycle time minus the allowance factor.
4. the normal cycle time divided by (1 + allowance factor).
5. the normal cycle time multiplied by (1 + allowance factor).

Difficulty: Hard

1. The normal times for basic, generic micro motions developed by an outside organization in a laboratory-type environment are referred to as
2. standard times.
3. normal times.
4. predetermined motion times.
5. elemental times.

Difficulty: Moderate

1. Advantages of using a predetermined motion time system include all of the following except
2. worker cooperation and compliance are not required.
3. ignores job context within which a single motion takes place.
4. workplace is not disrupted.
5. eliminates the need for subjectively determining performance ratings.

Difficulty: Moderate

1. As part of its quality-improvement program a company is conducting a time study for a particular job. The time study encompassed 10 job cycles, and the results include the following cumulative times and performance rating factors for each element.

The standard time for this job using an allowance factor of 16% is

1. 1.809 minutes.
2. 2.098 minutes.
3. 1.530 minutes.
4. 2.233 minutes.

Difficulty: Hard

Solution: ST = 1.809 × (1 + 0.16) = 2.028

1. As part of its quality-improvement program a company is conducting a time study for a particular job. The time study encompassed 10 job cycles, and the results include the following cumulative times and performance rating factors for each element. An allowance factor of 16% is assumed.

The normal cycle time for this job would be

1. 1.809 minutes.
2. 2.098 minutes.
3. 1.530 minutes.
4. 2.233 minutes.

Difficulty: Hard

Solution: NT = 1.809

1. As part of a time study a particular job was analyzed. The study included 20 job cycles and the following cumulative times and performance rating factors for each element were reported:

Assuming an allowance factor of 15%, the standard time for this job would be

• • 1. 4.35 minutes.
    2. 3.67 minutes.
    3. 2.712 minutes.
    4. 2.358 minutes.

Difficulty: Hard

Solution: ST = 2.358 × (1 + 1.15) = 2.712

1. How many cycles should be used in a time study in order to be 95% confident that the time-study average job cycle time is within 5% of the true average job cycle time? Assume that the average job cycle time is 2.67 minutes, and the standard deviation of the sample is 0.72 minutes.
2. 36 cycles
3. 72 cycles
4. 98 cycles
5. 112 cycles

Difficulty: Moderate

Solution: n = 112

1. How many cycles should be used in a time study in order to be 98% confident that the time-study average job cycle time is within 4% of the true average job cycle time? Assume that the average job cycle time is 4.25 minutes and the standard deviation of the sample is 0.65 minutes.
2. 55 cycles
3. 70 cycles
4. 80 cycles
5. 95 cycles

Difficulty: Moderate

Solution: n = 80

1. For a particular time study a company would like to be 95% confident that the average job cycle time is within 2% of the true average job cycle time. Assume that the average job cycle time was 6.53 minutes, and the standard deviation of the sample is 1.26 minutes. The number of cycles that should be used in this time study would be
2. 174.
3. 358.
4. 463.
5. 864.

Difficulty: Moderate

Solution: n = 358

1. A work sampling study is being conducted on a loading machine in a warehouse. How many observations should be taken if management wants to be 95% confident the estimate is within +6% of the actual proportion of time the loader is busy if management believes the loading machine is in use 70% of the time?
2. 125 observations
3. 175 observations
4. 225 observations
5. 275 observations

Difficulty: Moderate

1. Management believes a critical piece of equipment is busy 85% of the time. How many observations should be taken if management wants to be 98% confident the estimate is within +2.5% of the actual proportion of time the equipment is in use?
2. 250 observations
3. 525 observations
4. 757 observations
5. 1,108 observations

Difficulty: Moderate

Solution: n = 1,108 observations

1. How many observations should be taken to be 95% confident of being within +5% of the actual time a machine is busy if it is believed that the machine is in use 75% of the time?
2. 1,200 observations
3. 772 observations
4. 364 observations
5. 289 observations

Difficulty: Moderate

Solution: n = 289 observations

1. For a particular time study a company would like to be 90% confident that the average job cycle time is within 5% of the true average job cycle time. Assume that the average job cycle time is 15.76 minutes and the standard deviation of the sample is 3.2 minutes. The number of cycles that should be used in this time study would be
   1. 45.
   2. 93.
   3. 127.
   4. 236.

Difficulty: Moderate

Solution: n = 45

1. How many observations should be taken to be 90% confident of being within +2% of the actual time a machine is busy if it is believed that the machine is in use 70% of the time?
2. 2,021 observations
3. 1,421 observations
4. 789 observations
5. 365 observations

Difficulty: Moderate

Solution: n = 1,421 observations

1. As part of a time study a particular job was analyzed. The study included 20 job cycles and the following cumulative times and performance rating factors for each element were reported:

Assuming an allowance factor of 20% the standard time for this job would be

1. 10.08 minutes.
2. 12.10 minutes.
3. 14.73 minutes.
4. 16.58 minutes.

Difficulty: Hard

Solution: ST = 12.10 minutes

Short Answer Questions

30. Briefly discuss the advantages and disadvantages of a predetermined motion time system.

Difficulty: Moderate

31. List the steps in work sampling.

• 1. define the job activities
  2. determine the number of observations in the work sample
  3. determine the length of the sampling period
  4. conduct the work sampling study and record the observations
  5. periodically recompute the number of observations

Difficulty: Moderate

32. What is work sampling and what is its primary use?

Difficulty: Moderate

33. A company has 45 professional employees, who work analyzing and updating large files on computers. Management believes that these employees actually spend about 15% of their time waiting for files to be down- and uploaded, as well as copied to and read from their hard drives, and it is evaluating purchasing state-of-the-art solid state drives, whose speed is estimated to be 10 times faster than that of the existing computers. For this purpose, the company wants to perform a work sampling study to determine the proportion of time employees are waiting for files to be available, as described above. The company wants to determine this proportion within ±2%, with a 95% degree of confidence. The number of observations required is __________.

a) 1123

b) 1225

c) 1315

d) 1325

34. A company has 45 professional employees, who work analyzing and updating large files on computers. Preliminary, management believes that these employees actually spend about 15% of their time waiting for files to be down- and uploaded, as well as copied to and read from their hard drives, and it is evaluating purchasing state-of-the-art solid state drives, whose speed is estimated to be 10 times faster than that of the existing computers. For this purpose, the company wants to perform a work sampling study to determine the proportion of time employees are waiting for files to be available, as described above. The company wants to determine this proportion within ±2%, with a 95% degree of confidence. If after gathering some data, management estimates that the number of observations required is 1537, then the updated estimate of the proportion of time spent by employees waiting for files to be available is __________.

a) 18%

b) 19%

c) 20%

d) 21%

35. A company has 45 professional employees, who work analyzing and updating large files on computers. Management wishes to determine the proportion of time employees spend in each of these two activities. For a given allowable error margin and confidence level, which proportion p of time spent analyzing files would require the largest number of observations?

a) There is not enough information to answer the question.

b) p = 0.25

c) p = 0.33

d) p = 0.50

36. A company has 45 professional employees, who work analyzing and updating large files on computers. Management believes that these employees actually spend about 15% of their time waiting for files to be down- and uploaded, as well as copied to and read from their hard drives, and it is evaluating purchasing state-of-the-art solid state drives, whose speed is estimated to be 10 times faster than that of the existing computers. For this purpose, the company wants to perform a work sampling study to determine the proportion of time employees are waiting for files to be available, as described above. The company wants to determine this proportion within ±2%, with a 95% degree of confidence. However, management wants to limit the number of observations to 500. The actual degree of accuracy in determining the proportion would change from within ±2% to __________.

a) ±1%

b) ±2.5%

c) ±3%

d) ±3.5%