a)
To determine: The standard time for the operation.
Introduction: Time study is the basis that helps set the standard time; it would time a sample of the performance of the worker.
a)

Answer to Problem 30P
Thestandard time is calculated as 85.56 minutes.
Explanation of Solution
Given information:
Fatigue factor is given as 10% and personal-time factor is 10%. Accuracy rate is ±5%. The observed time and performance rating for each element is given as follows:
Element | Performance rating | Observation (minutes) | ||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | ||
Select correct mufflers | 110% | 4 | 5 | 4 | 6 | 4 | 15a | 4 |
Remove old muffler | 90% | 6 | 8 | 7 | 6 | 7 | 6 | 7 |
Weld/install new muffler | 105% | 15 | 14 | 15 | 12 | 15 | 16 | 13 |
Check/inspect work | 100% | 3 | 4 | 24a | 5 | 4 | 3 | 18a |
Complete paperwork | 130% | 5 | 6 | 8 | - | 7 | 6 | 7 |
a refers to the fact that the employee has lengthy conversations with the boss (not job-related)
Formulae to calculate standard time:
Calculate normal time:
Element | Performance rating | Observation (minutes) | Average time | Normal time | ||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | ||||
Select correct mufflers | 110% | 4 | 5 | 4 | 6 | 4 | 15a | 4 | 4.50 | 4.95 |
Remove old muffler | 90% | 6 | 8 | 7 | 6 | 7 | 6 | 7 | 6.71 | 6.04 |
Weld/install new muffler | 105% | 15 | 14 | 14 | 12 | 15 | 16 | 13 | 14.14 | 14.85 |
Check/inspect work | 100% | 3 | 4 | 24a | 5 | 4 | 3 | 18a | 3.80 | 3.80 |
Complete paperwork | 130% | 5 | 6 | 8 | - | 7 | 6 | 7 | 6.50 | 8.45 |
Excel worksheet:
Calculate the average time to select correct mufflers:
The average time is calculated by taking an average of the observation given, which is the summation of 4, 5, 4, 6, 4, and 4 and dividing the result by 6. Hence, the average is 4.5 minutes.
Note: The observation with (Xa) should not be considered while calculating the average time.
Calculate the average time to remove the old muffler:
The average time is calculated by taking an average of the observation given, which is the summation of 6, 8, 7, 6, 7, 6, and 7 and dividing the result by 7. Hence, the average is 6.71 minutes.
Calculate the average time to weld or install a new muffler:
The average time is calculated by taking an average of the observation given, which is the summation of 15, 14, 14, 12, 15, 16, and 13 and dividing the result by 7. Hence, the average is 14.14 minutes.
Calculate the average time to check or inspect work:
The average time is calculated by taking an average of the observation given, which is the summation of 3, 4, 5, 4, and 3 and dividing the result by 5. Hence, the average is 3.80 minutes.
Note: The observation with (Xa) should not be considered while calculating the average time.
Calculate the average time to complete paperwork:
The average time is calculated by taking an average of the observation given, which is the summation of 5, 6, 8, 7, 6, and 7 and dividing the result by 6. Hence, the average is 6.50 minutes.
Calculate the normal time to select correct mufflers:
The normal time is calculated by multiplying the average time and performance rating. Average time is calculated as 4.50 minutes and performance rating is given as 110%. Hence, the normal time is 4.95 minutes.
Calculate the normal time to remove the old muffler:
The normal time is calculated by multiplying the average time and performance rating. Average time is calculated as 6.71 minutes and performance rating is given as 90%. Hence, the normal time is 6.04 minutes.
Calculate the normal time to weld or install a new muffler:
The normal time is calculated by multiplying the average time and performance rating. Average time is calculated as 14.14 minutes and performance rating is given as 105%. Hence, the normal time is 14.85 minutes.
Calculate the normal time to check or inspect work:
The normal time is calculated by multiplying the average time and performance rating. Average time is calculated as 3.80 minutes and performance rating is given as 100%. Hence, the normal time is 3.80 minutes.
Calculate the normal time to complete paperwork:
The normal time is calculated by multiplying the average time and performance rating. Average time is calculated as 6.50 minutes and performance rating is given as 130%. Hence, the normal time is 8.45 minutes.
Calculate the total normal time:
The normal time is calculated by multiplying the average time and performance rating. Average time is calculated as 6.50 minutes and performance rating is given as 130%. Hence, the normal time is 8.45 minutes.
Normal time is calculated by adding the normal time to select correct mufflers, remove the old muffler, weld or install a new muffler, check or inspect work, and to complete paperwork.
Hence, the total normal time is 38.09 minutes.
Calculate the standard time:
The standard time is calculated by dividing the normal time with the value attained by subtracting the allowance factor from 1. Normal time is calculated as 38.09 minutes and allowance factor is calculated as the sum of fatigue factor, which is 10% and personal time factor, which is 10%.
Hence, the standard time is 47.6 minutes.
b)
To determine: The number of
Introduction: Thesample size is required to determine the number of observations that are necessary to find the true cycle time.
b)

Answer to Problem 30P
Thesample size to select correct mufflers is 53, to remove the old muffler is 20, to weld or install a new muffler is 14, to check or inspect work is 75, and to complete paperwork is 40 samples.
Explanation of Solution
Given information:
Confidence level is 95% and accuracy is ±5%.
Element | Performance rating | Observation (minutes) | ||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | ||
Select correct mufflers | 110% | 4 | 5 | 4 | 6 | 4 | 15a | 4 |
Remove old muffler | 90% | 6 | 8 | 7 | 6 | 7 | 6 | 7 |
Weld/install new muffler | 105% | 15 | 14 | 15 | 12 | 15 | 16 | 13 |
Check/inspect work | 100% | 3 | 4 | 24a | 5 | 4 | 3 | 18a |
Complete paperwork | 130% | 5 | 6 | 8 | - | 7 | 6 | 7 |
a refers to the fact that the employee has lengthy conversation with the boss (not job-related)
Formulae to determine the required number of observation:
n refers to number of observations required
z refers to the table value for confidence level
s refers to standard deviation
h refers to accuracy level
Determine the proper number of observations required:
Element | Performance rating | Observation (minutes) | Average time | s | Sample | ||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | |||||
Select correct mufflers | 110% | 4 | 5 | 4 | 6 | 4 | 15a | 4 | 4.50 | 0.836 | 53.1 |
Remove old muffler | 90% | 6 | 8 | 7 | 6 | 7 | 6 | 7 | 6.71 | 0.755 | 19.5 |
Weld/install new muffler | 105% | 15 | 14 | 14 | 12 | 15 | 16 | 13 | 14.14 | 1.345 | 13.9 |
Check/inspect work | 100% | 3 | 4 | 24a | 5 | 4 | 3 | 18a | 3.80 | 0.836 | 74.5 |
Complete paperwork | 130% | 5 | 6 | 8 | - | 7 | 6 | 7 | 6.50 | 1.048 | 40.0 |
Excel worksheet:
Calculate the standard deviation to select correct mufflers:
The standard deviation can be calculated by dividing two values. The first value can be calculated by adding the square of the value attained by subtracting the mean observed value from each observation. The second value can be attained by subtracting 1 from the number of samples and the result should be square rooted. Standard deviation to select correct mufflers is 0.836.
Calculate standard deviation to remove old muffler:
The standard deviation can be calculated by dividing two values. The first value can be calculated by adding the square of the value attained by subtracting the mean observed value from each observation. The second value can be attained by subtracting 1 from the number of samples and the result should be square rooted. Standard deviation to remove old muffler is 0.755.
Calculate standard deviation to weld or install new muffler:
The standard deviation can be calculated by dividing two values. The first value can be calculated by adding the square of the value attained by subtracting the mean observed value from each observation. The second value can be attained by subtracting 1 from the number of samples and the result should be square rooted. Standard deviation to weld or install new muffler is 1.345.
Calculate standard deviation to check or inspect work:
The standard deviation can be calculated by dividing two values. The first value can be calculated by adding the square of the value attained by subtracting the mean observed value from each observation. The second value can be attained by subtracting 1 from the number of samples and the result should be square rooted. Standard deviation to check or inspect work is 0.836.
Calculate standard deviation to complete paperwork:
The standard deviation can be calculated by dividing two values. The first value can be calculated by adding the square of the value attained by subtracting the mean observed value from each observation. The second value can be attained by subtracting 1 from the number of samples and the result should be square rooted. Standard deviation to check or inspect work is 1.048.
Calculate the sample size to select correct mufflers:
It is calculated by multiplying the z value of 1.96, the standard deviation that is given as 0.836, and dividing the resultant with the multiple of the accuracy level and the average observed time that is given as 0.05 and 4.5, respectively. Hence, the required number of observations is 53 samples.
Calculate the sample size to remove the old muffler:
It is calculated by multiplying the z value of 1.96, the standard deviation that is given as 0.755, and dividing the resultant with the multiple of the accuracy level and the average observed time that is given as 0.05 and 6.71, respectively. Hence, the required number of observations is 20 samples.
Calculate the sample size to weld or install a new muffler:
It is calculated by multiplying the z value of 1.96, the standard deviation that is given as 1.345, and dividing the resultant with the multiple of the accuracy level and the average observed time that is given as 0.05 and 14.14, respectively. Hence, the required number of observations is 14 samples.
Calculate the sample size to check or inspect work:
It is calculated by multiplying the z value of 1.96, the standard deviation that is given as 0.836, and dividing the resultant with the multiple of the accuracy level and the average observed time that is given as 0.05 and 3.8, respectively. Hence, the required number of observations is 75 samples.
Calculate the sample size to complete paperwork:
It is calculated by multiplying the z value of 1.96, the standard deviation that is given as 1.048, and dividing the resultant with the multiple of the accuracy level and the average observed time that is given as 0.05 and 6.5, respectively. Hence, the required number of observations is 40 samples.
Hence, the standard time for the process is 47.6 minutes. The sample size to select correct mufflers are 53, to remove the old muffler is 20, weld or install a new muffler is 14, to check or inspect work is 75 samples, and to complete paperwork is 40 samples.
Want to see more full solutions like this?
Chapter 10 Solutions
PRIN.OF OPERATIONS MANAGEMENT-MYOMLAB
- Dietary Management in a Nursing Home. As detailed as possible.arrow_forwardFor dietary management in a nursing home. As detailed as possible.arrow_forwardA small furniture manufacturer produces tables and chairs. Each product must go through three stages of the manufacturing process – assembly, finishing, and inspection. Each table requires 3 hours of assembly, 2 hours of finishing, and 1 hour of inspection. The profit per table is $120 while the profit per chair is $80. Currently, each week there are 200 hours of assembly time available, 180 hours of finishing time, and 40 hours of inspection time. Linear programming is to be used to develop a production schedule. Define the variables as follows: T = number of tables produced each week C= number of chairs produced each week According to the above information, what would the objective function be? (a) Maximize T+C (b) Maximize 120T + 80C (c) Maximize 200T+200C (d) Minimize 6T+5C (e) none of the above According to the information provided in Question 17, which of the following would be a necessary constraint in the problem? (a) T+C ≤ 40 (b) T+C ≤ 200 (c) T+C ≤ 180 (d) 120T+80C ≥ 1000…arrow_forward
- As much detail as possible. Dietary Management- Nursing Home Don't add any fill-in-the-blanksarrow_forwardMenu Planning Instructions Use the following questions and points as a guide to completing this assignment. The report should be typed. Give a copy to the facility preceptor. Submit a copy in your Foodservice System Management weekly submission. 1. Are there any federal regulations and state statutes or rules with which they must comply? Ask preceptor about regulations that could prescribe a certain amount of food that must be kept on hand for emergencies, etc. Is the facility accredited by any agency such as Joint Commission? 2. Describe the kind of menu the facility uses (may include standard select menu, menu specific to station, non-select, select, room service, etc.) 3. What type of foodservice does the facility have? This could be various stations to choose from, self-serve, 4. conventional, cook-chill, assembly-serve, etc. Are there things about the facility or system that place a constraint on the menu to be served? Consider how patients/guests are served (e.g. do they serve…arrow_forwardWork with the chef and/or production manager to identify a menu item (or potential menu item) for which a standardized recipe is needed. Record the recipe with which you started and expand it to meet the number of servings required by the facility. Develop an evaluation rubric. Conduct an evaluation of the product. There should be three or more people evaluating the product for quality. Write a brief report of this activity • Product chosen and the reason why it was selected When and where the facility could use the product The standardized recipe sheet or card 。 o Use the facility's format or Design one of your own using a form of your choice; be sure to include the required elements • • Recipe title Yield and portion size Cooking time and temperature Ingredients and quantities Specify AP or EP Procedures (direction)arrow_forward
- ASSIGNMENT: Inventory, Answer the following questions 1. How does the facility survey inventory? 2. Is there a perpetual system in place? 3. How often do they do a physical inventory? 4. Participate in taking inventory. 5. Which type of stock system does the facility use? A. Minimum stock- includes a safety factor for replenishing stock B. Maximum stock- equal to a safety stock plus estimated usage (past usage and forecasts) C. Mini-max-stock allowed to deplete to a safety level before a new order is submitted to bring up inventory up to max again D. Par stock-stock brought up to the par level each time an order is placed regardless of the amount on hand at the time of order E. Other-(describe) Choose an appropriate product and determine how much of an item should be ordered. Remember the formula is: Demand during lead time + safety stock = amount to order Cost out an inventory according to data supplied. Remember that to do this, you will need to take an inventory, and will need to…arrow_forwardHuman Relations, Systems, and Organization Assignments ORGANIZATION: Review the organization chart for the facility • Draw an organization chart for the department. • . Identify and explain the relationships of different units in the organization and their importance to maintain the food service department's mission. Include a copy in your weekly submission. There is a feature in PowerPoint for doing this should you want to use it. JOB ORGANIZATION: ⚫ A job description is a broad, general, and written statement for a specific job, based on the findings of a job analysis. It generally includes duties, purpose, responsibilities, scope, and working conditions of a job along with the job's title, and the name or designation of the person to whom the employee reports. Job description usually forms the basis of job specification. • Work with your preceptor or supervisor to identify a position for which you will write a job description. Include a copy of the job description you write in your…arrow_forwardASSIGNMENT: Production Sheet Watch at least 3 workers prepare foods. Write down what they do and the amount of time it takes for them to complete the task. Calculate the production cost. Example: Food Item: Green Beans Time Worker #1 Worker #2 Worker #3 Start End Time (Hours) Time Time Activity Activity Activity (Hours) (Hours) 11:45 am 12:01 pm 0.27 Steam and 0.05 Microwave blenderize pureed frozen green green beans beans 16.25 Total Production Time 3 minutes minutes Hourly Wage $16.07 $12.28 24% Benefits *** $3.86 $2.95 Labor Costs $5.37 $0.76 *** Check with facility to see Benefit %arrow_forward
- Foundations of Business (MindTap Course List)MarketingISBN:9781337386920Author:William M. Pride, Robert J. Hughes, Jack R. KapoorPublisher:Cengage LearningFoundations of Business - Standalone book (MindTa...MarketingISBN:9781285193946Author:William M. Pride, Robert J. Hughes, Jack R. KapoorPublisher:Cengage Learning
- Understanding Management (MindTap Course List)ManagementISBN:9781305502215Author:Richard L. Daft, Dorothy MarcicPublisher:Cengage Learning


