Question 1

Eight instances of a worker doing a task were observed as follows: $$\begin{array} { l r r r r r r r r } 
\text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \
\hline \text { Time (seconds) } & 17 & 18 & 15 & 14 & 13 & 15 & 16 & 12
\end{array}$$ If the person observed worked at a pace that is 80 percent of normal, what should be the normal time for this task?

Accepted Answer

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Question 2

A methods and measurements analyst for Digital Devices needs to develop a time standard for the task of assembling a computer mouse. In a preliminary study, she observed one of her workers perform this task six times with the following results: $$\begin{array} { l r r r r r r } 
\text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 \
\hline \text { Time (seconds) } & 46 & 38 & 40 & 34 & 42 & 40
\end{array}$$ What is the standard time for this task if the employee worked at a 20 percent faster pace than average and an allowance of 25 percent of the workday is used?

Accepted Answer

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Question 3

The manager of Lawn and Garden Services would like to estimate the proportion of her employees' time spent performing various gardening and lawn care activities. She has made 400 random observations of a typical worker, with the following results: $$\begin{array} { l r } 
\text { Activity } & \text { Times Observed } \
\hline \text { Mowing } & 200 \
\text { Trimming } & 80 \
\text { Raking } & 40 \
\text { Miscellaneous } & 80
\end{array}$$ How confident can the manager be that the true proportion of time spent mowing is between .45 and .55?

Accepted Answer

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Question 4

The manager of Lawn and Garden Services would like to estimate the proportion of her employees' time spent performing various gardening and lawn care activities. She has made 400 random observations of a typical worker, with the following results: $$\begin{array} { l r } 
\text { Activity } & \text { Times Observed } \
\hline \text { Mowing } & 200 \
\text { Trimming } & 80 \
\text { Raking } & 40 \
\text { Miscellaneous } & 80
\end{array}$$ What is the most likely true proportion of time spent mowing?

Accepted Answer

The proportion of time spent mowing is calculated by dividing the number of times mowing was observed by the total number of observations: 200/400 = 0.5.

Question 5

An analyst has observed 28 work cycles, for which the average cycle time was five minutes and the performance rating was 1.05. Allowances for the department are 25 percent of job time. What standard time is appropriate for this job?

Accepted Answer

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Question 6

A work sampling study of kitchen help is to be designed. The study will be conducted over a nine-day period. The kitchen help works a seven-hour shift. Determine the day, hour, and minute of five observations using the random digits listed below. $$\begin{array} { l r r r r r r r r r r r r r r } 
\text { Day } & 1 & 8 & 4 & 4 & 1 & 1 & 2 & 3 & 1 & 9 & 0 & 8 & 7 & 3 \
\text { Hour } & 7 & 3 & 8 & 4 & 7 & 9 & 1 & 3 & 2 & 4 & 9 & 6 & 3 & 5 \
\text { Minute } & 71 & 32 & 13 & 74 & 35 & 26 & 87 & 48 & 59 & 50 & 11 & 22 & 13 & 64
\end{array}$$
Arrange observations chronologically.

Accepted Answer

The answer of A work sampling study of kitchen help...

Question 7

The manager of Lawn and Garden Services would like to estimate the proportion of her employees' time spent performing various gardening and lawn care activities. She has made 400 random observations of a typical worker, with the following results: $$\begin{array} { l r } 
\text { Activity } & \text { Times Observed } \
\hline \text { Mowing } & 200 \
\text { Trimming } & 80 \
\text { Raking } & 40 \
\text { Miscellaneous } & 80
\end{array}$$ If the manager wants to be 95.44 percent confident that the true proportion of time spent mowing is within .02 (plus or minus) of the sample proportion, what should be her sample size?

Accepted Answer

The answer of The manager of Lawn and Garden Services...

Question 8

A methods and measurements analyst for Digital Devices needs to develop a time standard for the task of assembling a computer mouse. In a preliminary study, she observed one of her workers perform this task six times with the following results: $$\begin{array} { l r r r r r r } 
\text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 \
\hline \text { Time (seconds) } & 46 & 38 & 40 & 34 & 42 & 40
\end{array}$$ What is the normal time for this task if the employee worked at a 20 percent faster pace than average?

Accepted Answer

The answer of A methods and measurements analyst for Digital...

Question 9

A methods and measurements analyst for Digital Devices needs to develop a time standard for the task of assembling a computer mouse. In a preliminary study, she observed one of her workers perform this task six times with the following results: $$\begin{array} { l r r r r r r } 
\text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 \
\hline \text { Time (seconds) } & 46 & 38 & 40 & 34 & 42 & 40
\end{array}$$ How many observations should be made if she wants to be 86.64 percent confident that the maximum error in the observed time is .5 second? Assume that the standard deviation of the task time is four seconds.

Accepted Answer

To determine the sample size required for the study, we use the following formula:

$n = (\dfrac{z\sigma}{E})^2$

Where: 
$n$ = sample size 
$z$ = z-value for desired confidence level (86.64 percent = 1.5 standard deviations, approximately) 
$\sigma$ = standard deviation of the task time (given as 4 seconds)
$E$ = maximum error in observed time (given as 0.5 seconds)

Substituting the given values, we get:

$n = (\dfrac{(1.5)(4)}{0.5})^2 = 144$

Therefore, the analyst should make 144 observations to be 86.64 percent confident that the maximum error in the observed time is 0.5 second.

The correct answer is (D) 144.

Question 10

Eight instances of a worker doing a task were observed as follows: $$\begin{array} { l r r r r r r r r } 
\text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \
\hline \text { Time (seconds) } & 17 & 18 & 15 & 14 & 13 & 15 & 16 & 12
\end{array}$$ If the person observed worked at a pace that is 80 percent of normal, and if the appropriate allowance for this task is 25 percent of job time, what should be the standard time?

Accepted Answer

The answer of Eight instances of a worker doing a...

Question 11

Eight instances of a worker doing a task were observed as follows: $$\begin{array} { l r r r r r r r r } 
\text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \
\hline \text { Time (seconds) } & 17 & 18 & 15 & 14 & 13 & 15 & 16 & 12
\end{array}$$ What is the observed time for this task?

Accepted Answer

The answer of Eight instances of a worker doing a...

Question 12

An initial time study resulted in an average observed time of 2.2 minutes per cycle, and a standard deviation of .3 minutes per cycle. The performance rating was 1.20. What sample size, including the 20 observations in the initial study, would be necessary to have a confidence of 95.44 percent that the observed time was within 4 percent of the true value?

Accepted Answer

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Question 13

A time study of a job produced the following: average cycle time = 1.5 minutes, performance rating = 1.15. Allowances are 18 percent of the workday (480 minutes). Determine the standard time for this job.

Accepted Answer

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Question 14

A work sampling study of dockworkers must be set up. There will be a large number of random observations. However, for this exercise, determine an observation schedule (arranged chronologically) for six observations. Assume workers are on the docks for eight hours a day, and that the study will be done over a 60-day period. Use the random digits listed below. $$\begin{array} { l r r r r r r r r r r r r r r r r r r r } 
\text { Day } & 81 & 22 & 53 & 94 & 95 & 96 & 17 & 28 & 39 & 70 & 61 & 12 & 43 & 04 & 25 & 86 & 27 & 28 & 19 \
\text { Hour } & 1 & 3 & 9 & 6 & 7 & 3 & 5 & 4 & 3 & 2 & 4 & 9 & 7 & 7 & 1 & 3 & 2 & 5 & 8 \
\text { Minute } & 03 & 19 & 25 & 70 & 81 & 93 & 02 & 18 & 27 & 33 & 44 & 53 & 05 & 10 & 28 & 33 & 41 & 53 & 66
\end{array}$$

Accepted Answer

The answer of A work sampling study of dockworkers must...

Question 15

The manager of Lawn and Garden Services would like to estimate the proportion of her employees' time spent performing various gardening and lawn care activities. She has made 400 random observations of a typical worker, with the following results: $$\begin{array} { l r } 
\text { Activity } & \text { Times Observed } \
\hline \text { Mowing } & 200 \
\text { Trimming } & 80 \
\text { Raking } & 40 \
\text { Miscellaneous } & 80
\end{array}$$ Between what limits can the manager be 68.26 percent confident about the true proportion of time spent mowing?

Accepted Answer

To estimate the proportion of time spent mowing, we need to find the proportion of times mowing was observed out of the total observations.

Proportion of time spent mowing = 200/400 = 0.5

To find the confidence interval for this proportion, we will use the normal approximation to the binomial distribution, since we have a large sample size (n=400) and the proportion of success (mowing) is not too close to 0 or 1.

We will use the formula:

CI = p ± z*sqrt(p*(1-p)/n)

where p is the sample proportion, z* is the z-score corresponding to the desired confidence level (which is 68.26% in this case), and n is the sample size.

From the table of standard normal distribution, the z-score for a 68.26% confidence level is approximately 1.

Plugging in the values we get:

CI = 0.5 ± 1*sqrt(0.5*(1-0.5)/400)
CI = 0.5 ± 0.049
CI = (0.451, 0.549)

Therefore, we can be 68.26% confident that the true proportion of time spent mowing is between 0.451 and 0.549.

The only answer choice that contains these limits is B: 0.475 and 0.525.

Question 16

The manager of Lawn and Garden Services would like to estimate the proportion of her employees' time spent performing various gardening and lawn care activities. She has made 400 random observations of a typical worker, with the following results: $$\begin{array} { l r } 
\text { Activity } & \text { Times Observed } \
\hline \text { Mowing } & 200 \
\text { Trimming } & 80 \
\text { Raking } & 40 \
\text { Miscellaneous } & 80
\end{array}$$ What is the probability that the true proportion of time spent mowing is exactly equal to the sample proportion?

Accepted Answer

In order to determine the probability that the true proportion of time spent mowing is exactly equal to the sample proportion, we need to conduct a hypothesis test. However, the information given in the question is not sufficient to carry out such a test, as we do not have an estimate of the population proportion, nor do we know the sample size or level of significance.
Therefore, we cannot determine the probability and the correct answer is A, 0.

Question 17

Eight instances of a worker doing a task were observed as follows: $$\begin{array} { l r r r r r r r r } 
\text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \
\hline \text { Time (seconds) } & 17 & 18 & 15 & 14 & 13 & 15 & 16 & 12
\end{array}$$ If the person observed worked at a pace that is 20 percent faster than average, what should be the normal time for this task?

Accepted Answer

The answer of Eight instances of a worker doing a...

Question 18

A methods and measurements analyst for Digital Devices needs to develop a time standard for the task of assembling a computer mouse. In a preliminary study, she observed one of her workers perform this task six times with the following results: $$\begin{array} { l r r r r r r } 
\text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 \
\hline \text { Time (seconds) } & 46 & 38 & 40 & 34 & 42 & 40
\end{array}$$ What is the standard time for this task if the employee worked at a 20 percent faster pace than average and an allowance of 25 percent of job time is used?

Accepted Answer

The answer of A methods and measurements analyst for Digital...

Question 19

A work sampling study is needed that will estimate the percentage of time a postal clerk spends selling stamps as opposed to other duties. Determine the necessary sample size to estimate that proportion with a confidence of 99.74 percent to within 3 percent, for these cases:
(1) No information is currently available concerning that proportion.
(2) The proportion is probably no more than 15 percent.

Accepted Answer

The answer of A work sampling study is needed that...

Question 20

How many observations would be required in a time study in order to obtain 95 percent confidence that the average time observed was no more than 0.6 minutes from the true mean, assuming a standard deviation of cycle time of 1.8 minutes?

Accepted Answer

The answer of How many observations would be required in...

Quiz 7: Work Design and Measurement

An analyst has observed 28 work cycles, for which the average cycle time was five minutes and the performance rating was 1.05. Allowances for the department are 25 percent of job time. What standard time is appropriate for this job?

Eight instances of a worker doing a task were observed as follows: $\begin{array} { l r r r r r r r r } \text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\\hline \text { Time (seconds) } & 17 & 18 & 15 & 14 & 13 & 15 & 16 & 12\end{array}$ What is the observed time for this task?

A time study of a job produced the following: average cycle time = 1.5 minutes, performance rating = 1.15. Allowances are 18 percent of the workday (480 minutes). Determine the standard time for this job.

How many observations would be required in a time study in order to obtain 95 percent confidence that the average time observed was no more than 0.6 minutes from the true mean, assuming a standard deviation of cycle time of 1.8 minutes?