
a)
To determine: The normal time for the operation.
Introduction: The 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 28P
The normal time is calculated as 77.8 minutes.
Explanation of Solution
Given information:
The observed time and performance rating for each element is given as follows:
Element | Performance rating | Observation (minutes) | ||||
1 | 2 | 3 | 4 | 5 | ||
Prepare daily reports | 120 | 35 | 40 | 33 | 42 | 39 |
Photocopy results | 110 | 12 | 10 | 36a | 15 | 13 |
Label and package reports | 90 | 3 | 3 | 5 | 5 | 4 |
Distribute reports | 85 | 15 | 18 | 21 | 17 | 45b |
a refers to the photocopying machine being broken
b refers to the delay in allowance factor
Formulae to calculate normal time:
Calculate normal time:
Element | Performance rating | Observation (minutes) | Average time | Normal time | ||||
1 | 2 | 3 | 4 | 5 | ||||
Prepare daily reports | 120% | 35 | 40 | 33 | 42 | 39 | 37.8 | 45.36 |
Photocopy results | 110% | 12 | 10 | 36a | 15 | 13 | 12.5 | 13.75 |
Label and package reports | 90% | 3 | 3 | 5 | 5 | 4 | 4 | 3.6 |
Distribute reports | 85% | 15 | 18 | 21 | 17 | 45b | 17.75 | 15.09 |
Calculate the average time to prepare daily reports:
The average time is calculated by taking an average of the observation given, which is a summation of 35, 40, 33, 42, and 39 and dividing the result by 5. Hence, the average is 37.8 minutes.
Calculate the average time to photocopy results:
The average time is calculated by taking an average of the observation given, which is a summation of 12, 10, 15, and 13 and dividing the result by 4. Hence, the average is 12.5 minutes.
Note: The observation with (Xa) should not be considered while calculating the average time.
Calculate the average time to label and package reports:
The average time is calculated by taking an average of the observation given, which is a summation of 3, 3, 5, 5, and 4 and dividing the result by 5. Hence, the average is 4 minutes.
Calculate the average time to distribute reports:
The average time is calculated by taking an average of the observation given, which is a summation of 15, 18, 21, and 17 and dividing the result by 4. Hence, the average is 17.75 minutes.
Note: The observation with (Xb) should not be considered while calculating the average time.
Calculate the normal time to prepare daily reports:
The normal time is calculated by multiplying average time and performance rating. The average time is calculated as 37.8 minutes, and performance rating is given as 120%. Hence, the normal time is 45.36 minutes.
Calculate the normal time to photocopy results:
The normal time is calculated by multiplying average time and performance rating. The average time is calculated as 12.50 minutes, and performance rating is given as 110%. Hence, the normal time is 13.75 minutes.
Calculate the normal time to label and package reports:
The normal time is calculated by multiplying average time and performance rating. The average time is calculated as 4.0 minutes, and performance rating is given as 90%. Hence, the normal time is 3.6 minutes.
Calculate the normal time to distribute reports:
The normal time is calculated by multiplying average time and performance rating. The average time is calculated as 17.75 minutes, and performance rating is given as 85%. Hence, the normal time is 15.09 minutes.
Calculate the total normal time:
The normal time is calculated by adding the normal time to prepare daily reports, photocopy results, label and package reports, and distribute reports.
Hence, the total normal time is 77.8 minutes.
b)
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.
b)

Answer to Problem 28P
Thestandard time is calculated as 91.53 minutes.
Explanation of Solution
Given information:
The allowance is given as 15%. The observed time and performance rating for each element is given as follows:
Element | Performance rating | Observation (minutes) | ||||
1 | 2 | 3 | 4 | 5 | ||
Prepare daily reports | 120 | 35 | 40 | 33 | 42 | 39 |
Photocopy results | 110 | 12 | 10 | 36a | 15 | 13 |
Label and package reports | 90 | 3 | 3 | 5 | 5 | 4 |
Distribute reports | 85 | 15 | 18 | 21 | 17 | 45b |
a refers to the photocopying machine being broken
b refers to the delay in allowance factor
Formula to calculate standard time:
Calculate 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 77.8 minutes and allowance factor is calculated as 15%
Hence, standard time is 91.53 minutes.
c)
To determine: The number of the
Introduction: The sample size is required to determine the number of observations that are necessary to find the true cycle time.
c)

Answer to Problem 28P
The sample size to prepare reports is 15, to photocopy results is 44, label, and package reports is 96, and to distribute reports is 31 samples.
Explanation of Solution
Given information:
The confidence level is 95% and accuracy is ±5%.
Element | Performance rating | Observation (minutes) | ||||
1 | 2 | 3 | 4 | 5 | ||
Prepare daily reports | 120 | 35 | 40 | 33 | 42 | 39 |
Photocopy results | 110 | 12 | 10 | 36a | 15 | 13 |
Label and package reports | 90 | 3 | 3 | 5 | 5 | 4 |
Distribute reports | 85 | 15 | 18 | 21 | 17 | 45b |
Formula to determine the required number of observation:
n refers to the number of observations required
z refers to the table value for the confidence level
s refers to the standard deviation
h refers to an accuracy level
x(bar) refers to the average observed time
Determine a proper number of observation required:
Element | Mean observed time | s | Sample |
Prepare daily reports | 37.8 | 3.7 | 15 |
Photocopy results | 12.5 | 2.1 | 44 |
Label and package reports | 4 | 1 | 96 |
Distribute reports | 17.75 | 2.5 | 31 |
Calculate the standard deviation to prepare daily reports:
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 results should be square rooted. The standard deviation to prepare the daily report is 3.7.
Calculate the standard deviation to photocopy results:
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 results should be square rooted. The standard deviation to photocopy results is 2.1.
Calculate the standard deviation to label and package reports:
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 results should be square rooted. The standard deviation to label and package reports is 1.
Calculate the standard deviation to distribute reports:
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 results should be square rooted. The standard deviation to distribute reports is 2.5.
Calculate the sample size to prepare daily reports:
It is calculated by multiplying the z value of 1.96, the standard deviation that is given as 3.7, and dividing the result with the multiple of the accuracy level and average observed time that is given as 0.05 and 37.8, respectively. Hence, the required number of observations is 15 samples.
Calculate the sample size to photocopy results:
It is calculated by multiplying the z value of 1.96, the standard deviation that is given as 2.1, and dividing the result with the multiple of the accuracy level and average observed time that is given as 0.05 and 12.5, respectively. Hence, the required number of observations is 44 samples.
Calculate the sample size to label and package reports:
It is calculated by multiplying the z value of 1.96, the standard deviation that is given as 1, and dividing the result with the multiple of the accuracy level and average observed time that is given as 0.05 and 4, respectively. Hence, the required number of observations is 96 samples.
Calculate the sample size to distribute reports:
It is calculated by multiplying the z value of 1.96, the standard deviation that is given as 2.5, and dividing the result with the multiple of the accuracy level and average observed time that is given as 0.05 and 17.75, respectively. Hence, the required number of observations is 31 samples.
Hence, the normal time for the process is 77.8 minutes and standard time for the process is 91.53 minutes. The sample size to prepare reports is 15, to photocopy results is 44, label and package reports are 96, and to distribute reports is 31 samples.
Want to see more full solutions like this?
Chapter 10 Solutions
EBK PRINCIPLES OF OPERATIONS MANAGEMENT
- The Donald Fertilizer Company produces industrial chemical fertilizers. The projected manufacturing requirements (in gallons) for the next four quarters are 60,000, 90,000, 90,000, and 140,000 respectively. A level workforce is desired, relying only on anticipation inventory as a supply option. Stockouts and backorders are to be avoided, as are overtime and undertime. a. Determine the quarterly production rate required to meet total demand for the year, and minimize the anticipation inventory that would be left over at the end of the year. Beginning inventory is 0. The quarterly production rate is ☐ gallons. (Enter your response as an integer.)arrow_forwardHow would you design an operations plan and schedule for a new product/service? What factors would you consider and what challenges would you anticipate? Why are these factors and challenges relevant and how would you address them?arrow_forwardYou are the newly appointed CEO of TechSouth, a South African multinational technology company based in Cape Town. TechSouth specialises in manufacturing smartphones, laptops, and smart home devices. The company has a significant presence in the African market and has recently expanded into Europe and Asia. However, TechSouth is facing several critical challenges:· Declining Market Share - Over the past three years, TechSouth has lost considerable market share to both localcompetitors and international giants like Samsung and Apple. The company's products are perceived as outdated and lacking innovation.· Employee Engagement Issues - Recent employee surveys indicate low morale and engagement levels, particularly among the younger workforce, leading to high turnover rates. Many employees feel disconnected from the company's vision and mission.· Siloed Departments - The organizational structure at TechSouth is highly siloed, with departments operatingindependently rather than…arrow_forward
- What is the best way to manage emotions and thoughts? How to work through Emotions and thoughts?arrow_forwardWhat are the emotions or stressful thoughts? What are the differences between them? How can we work through the emotions or stressful thoughts? How can we avoid or prevent emotions or stressful thoughts from happening or occurring? What are the obstacles?arrow_forwardMain Challenges at TechInnovateStrategic DirectionTechInnovate's board of directors is pushing for a more aggressive expansion into emerging markets, particularly in Africaand Southeast Asia. However, there's internal disagreement about whether to focus on these new markets or consolidatetheir position in existing ones. Sarah Chen favors rapid expansion, while some senior executives advocate for a morecautious approach.Ethical ConcernsThe company's AI algorithms have come under scrutiny for potential biases, particularly in facial recognition technology.There are concerns that these biases disproportionately affect minority groups. Some employees have voiced ethicalconcerns about selling this technology to law enforcement agencies without addressing these issues.Team Leadership and DiversityTechInnovate's leadership team is predominantly male and Western, despite its global presence. There's growing pressurefrom employees and some board members to diversify the leadership team to…arrow_forward
- Sarah Anderson, the Marketing Manager at Exeter Township's Cultural Center, is conducting research on the attendance history for cultural events in the area over the past ten years. The following data has been collected on the number of attendees who registered for events at the cultural center. Year Number of Attendees 1 700 2 248 3 633 4 458 5 1410 6 1588 7 1629 8 1301 9 1455 10 1989 You have been hired as a consultant to assist in implementing a forecasting system that utilizes various forecasting techniques to predict attendance for Year 11. a) Calculate the Three-Period Simple Moving Average b) Calculate the Three-Period Weighted Moving Average (weights: 50%, 30%, and 20%; use 50% for the most recent period, 30% for the next most recent, and 20% for the oldest) c) Apply Exponential Smoothing with the smoothing constant alpha = 0.2. d) Perform a Simple Linear Regression analysis and provide the adjusted…arrow_forwardRuby-Star Incorporated is considering two different vendors for one of its top-selling products which has an average weekly demand of 70 units and is valued at $90 per unit. Inbound shipments from vendor 1 will average 390 units with an average lead time (including ordering delays and transit time) of 4 weeks. Inbound shipments from vendor 2 will average 490 units with an average lead time of 2 weeksweeks. Ruby-Star operates 52 weeks per year; it carries a 4-week supply of inventory as safety stock and no anticipation inventory. Part 2 a. The average aggregate inventory value of the product if Ruby-Star used vendor 1 exclusively is $enter your response here.arrow_forwardSam's Pet Hotel operates 50 weeks per year, 6 days per week, and uses a continuous review inventory system. It purchases kitty litter for $13.00 per bag. The following information is available about these bags: > Demand 75 bags/week > Order cost = $52.00/order > Annual holding cost = 20 percent of cost > Desired cycle-service level = 80 percent >Lead time = 5 weeks (30 working days) > Standard deviation of weekly demand = 15 bags > Current on-hand inventory is 320 bags, with no open orders or backorders. a. Suppose that the weekly demand forecast of 75 bags is incorrect and actual demand averages only 50 bags per week. How much higher will total costs be, owing to the distorted EOQ caused by this forecast error? The costs will be $higher owing to the error in EOQ. (Enter your response rounded to two decimal places.)arrow_forward
- Yellow Press, Inc., buys paper in 1,500-pound rolls for printing. Annual demand is 2,250 rolls. The cost per roll is $625, and the annual holding cost is 20 percent of the cost. Each order costs $75. a. How many rolls should Yellow Press order at a time? Yellow Press should order rolls at a time. (Enter your response rounded to the nearest whole number.)arrow_forwardPlease help with only the one I circled! I solved the others :)arrow_forwardOsprey Sports stocks everything that a musky fisherman could want in the Great North Woods. A particular musky lure has been very popular with local fishermen as well as those who buy lures on the Internet from Osprey Sports. The cost to place orders with the supplier is $40/order; the demand averages 3 lures per day, with a standard deviation of 1 lure; and the inventory holding cost is $1.00/lure/year. The lead time form the supplier is 10 days, with a standard deviation of 2 days. It is important to maintain a 97 percent cycle-service level to properly balance service with inventory holding costs. Osprey Sports is open 350 days a year to allow the owners the opportunity to fish for muskies during the prime season. The owners want to use a continuous review inventory system for this item. Refer to the standard normal table for z-values. a. What order quantity should be used? lures. (Enter your response rounded to the nearest whole number.)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


