labor productivity

Portfolio 1 Part 2 (chapter 2).

1.
value:
4.00 points

A catering company prepared and served 350 meals at an anniversary celebration last week using eleven workers. The week before, five workers prepared and served 240 meals at a wedding reception.

a1. Calculate the labor productivity for each event. (Round your answers to 1 decimal place.)

Anniversary
meals/worker
Wedding
meals/worker

a2. For which event was the labor productivity higher?

Anniversary

Wedding

2.
value:
4.00 points

The manager of a crew that installs carpeting has tracked the crew’s output over the past several weeks, obtaining these figures:

Week Crew Size Yards Installed
1 4 96
2 3 65
3 4 97
4 2 52
5 3 60
6 2 54
________________________________________

a. Compute the labor productivity for each of the weeks. (Round your answers to 2 decimal places.)

Week Crew size Labour productivity
(Yards/Person)
1 4 2 3 3 4 4 2 5 3 6 2 ________________________________________
b. Which crew size works best?

A crew of seems to work best. 3.
value:
4.00 points

Compute the multifactor productivity measure for each of the weeks shown for production of chocolate bars. Assume 40-hour weeks and an hourly wage of $12. Overhead is 1.5 times weekly labor cost. Material cost is $7 per pound. (Round your answers to 2 decimal places.)

Week Output (units) Workers Material (lbs)
1 29,000 5 480
2 34,000 7 480
3 31,000 8 510
4 36,000 8 510
________________________________________

Week MFP
1 2 3 4 ________________________________________
4.
value:
4.00 points

A company that makes shopping carts for supermarkets and other stores recently purchased some new equipment that reduces the labor content of the jobs needed to produce the shopping carts. Prior to buying the new equipment, the company used 6 workers, who produced an average of 70 carts per hour. Workers receive $17 per hour, and machine cost was $50 per hour. With the new equipment, it was possible to transfer one of the workers to another department, and equipment cost increased by $12 per hour while output increased by 5 carts per hour.

a. Compute labor productivity under each system. Use carts per worker per hour as the measure of labor productivity. (Round your answers to 2 decimal places.)

Before
carts per worker per hour
After
carts per worker per hour

b. Compute the multifactor productivity under each system. Use carts per dollar cost (labor plus equipment) as the measure. (Round your answers to 2 decimal places.)

Before
carts/$1
After
carts/$1

c. Comment on the changes in productivity according to the two measures. (Round your intermediate calculations and final answers to 2 decimal places. Omit the “%” signs in your response.)

Labor productivity by % Multifactor productivity by %
5.
value:
4.00 points

An operation has a 30 percent scrap rate. As a result, 62 pieces per hour are produced. What is the potential increase in labor productivity that could be achieved by eliminating the scrap? (Round your intermediate calculations to 3 decimal places and final answer to 1 decimal place. Omit the “%” sign in your response.)

This would amount to an increase of % 6.
value:
5.00 points

A manager checked production records and found that a worker produced 172 units while working 40 hours. In the previous week, the same worker produced 120 units while working 30 hours.

a. Compute Current period productivity and Previous period productivity. (Round your answers to 2 decimal places.)

Current period productivity
Units / hr
Previous period productivity
Units / hr
________________________________________

b. Did the worker’s productivity increase, decrease, or remain the same? (Round your intermediate calculations and final answer to 2 decimal places. Omit the “%” sign in your response.)

Worker’s productivity by % 7.
value:
5.00 points

The following table shows data on the average number of customers processed by several bank service units each day. The hourly wage rate is $30, the overhead rate is 1.0 times labor cost, and material cost is $8 per customer.

Unit Employees Customers Processed / Day
A 3 38
B 6 42
C 8 54
D 3 26
________________________________________

a. Compute the labor productivity and the multifactor productivity for each unit. Use an eight-hour day for multifactor productivity. (Round your “Labor Productivity” answers to 1 decimal place and “Multifactor Productivity” answers to 3 decimal places.)

Unit Labor
Productivity Multifactor Productivity
A
B
C
D
________________________________________

b. Suppose a new, more standardized procedure is to be introduced that will enable each employee to process one additional customer per day. Compute the expected labor and multifactor productivity rates for each unit. (Round your “Labor Productivity” answers to 1 decimal place and “Multifactor Productivity” answers to 4 decimal places.)

Unit Labor
Productivity Multifactor
Productivity
A
B
C
D
________________________________________
8.
value:
5.00 points

A property title search firm is contemplating using online software to increase its search productivity. Currently an average of 65 minutes is needed to do a title search. The researcher cost is $1.7 per minute. Clients are charged a fee of $490. Company A’s software would reduce the average search time by 12 minutes, at a cost of $3.5 per search. Company B’s software would reduce the average search time by 16 minutes at a cost of $5.3 per search.

a. Calculate the productivity in terms of revenue per dollar of input. (Round your intermediate calculations and final answers to 2 decimal places. Omit the “$” sign in your response.)

Approach Productivity per
Dollar Input
Current $ Company A $ Company B $ ________________________________________

b. Which option would have the highest productivity in terms of revenue per dollar of input?

Company A

Company B

Both

9.
value:
5.00 points

A company offers ID theft protection using leads obtained from client banks. Three employees work 40 hours a week on the leads, at a pay rate of $40 per hour per employee. Each employee identifies an average of 2,700 potential leads a week from a list of 5,000. An average of 5 percent of potential leads actually sign up for the service, paying a one-time fee of $75. Material costs are $1,100 per week, and overhead costs are $11,000 per week.

Calculate the multifactor productivity for this operation in fees generated per dollar of input. (Round your answer to 2 decimal places.)

Multifactor productivity
Portfolio 1 Part 3 (chapter 3)
1.
value:
5.00 points

A commercial bakery has recorded sales (in dozens) for three products, as shown below:

Day Blueberry Muffins Cinnamon Buns Cupcakes
1 31 15 45
2 31 14 12
3 33 16 16
4 31 16 48
5 39 22 21
6 30 23 16
7 32 17 12
8 36 19 48
9 29 18 17
10 32 20 19
11 38 21 10
12 31 22 50
13 35 23 18
14 33 31 15
15 34 33 13
________________________________________

a. Predict orders for the following day for each of the products using an appropriate naive method.

Blueberry Muffin : The forecast is
Cinnamon Buns : The forecast is
Cupcakes : The forecast is
________________________________________

b. What should the use of sales data instead of demand imply?

The use of sales data instead of demand implies that adequately reflect . We are assuming that no stock-outs occurred because demand equals sales if there are no shortages.
2.
value:
5.00 points

National Scan, Inc., sells radio frequency inventory tags. Monthly sales for a seven-month period were as follows:

Month Sales
(000)Units
Feb. 18
Mar. 17
Apr. 12
May. 22
Jun. 15
Jul. 21
Aug. 26
________________________________________

b. Forecast September sales volume using each of the following:

(1) A linear trend equation.(Round your intermediate calculations and final answer to 2 decimal places.)

Yt thousands
(2) A five-month moving average. (Round your answer to 2 decimal places.)

Moving average thousands
(3) Exponential smoothing with a smoothing constant equal to .50, assuming a March forecast of 15(000). (Round your intermediate calculations and final answer to 2 decimal places.)

Forecast thousands
(4) The naive approach.

Naive approach thousands
(5) A weighted average using .60 for August, .20 for July, and .20 for June. (Round your answer to 2 decimal places.)

Weighted average thousands 3.
value:
6.00 points

A dry cleaner uses exponential smoothing to forecast equipment usage at its main plant. August usage was forecasted to be 60 percent of capacity; actual usage was 65 percent of capacity. A smoothing constant of 0.3 is used.

a. Prepare a forecast for September. (Round your final answer to 2 decimal places.)

Forecast for September percent of capacity
b. Assuming actual September usage of 70 percent, prepare a forecast for October usage. (Round your answer to 2 decimal places.)

Forecast for October percent of capacity 4.
value:
6.00 points

An electrical contractor’s records during the last five weeks indicate the number of job requests:

Week: 1 2 3 4 5
Requests: 23 25 21 24 25
________________________________________

Predict the number of requests for week 6 using each of these methods:

a. Naive.
Number of requests
b. A four-period moving average. (Round your answer to 2 decimal places.)
Number of requests
c. Exponential smoothing with a = .40. Use 23 for week 2 forecast. (Round your intermediate calculations and final answers to 2 decimal places.)
Number of Requests
F3 F4 F5 F6 ________________________________________
5.
value:
6.00 points

A cosmetics manufacturer’s marketing department has developed a linear trend equation that can be used to predict annual sales of its popular Hand & Foot Cream.

Ft = 90 + 13t

where

Ft = Annual Sales (000 bottles)
t = 0 corresponds to 1990

a. Are annual sales increasing or decreasing? By how much?

Annual sales are by thousands bottles per year.
b. Predict annual sales for the year 2006 using the equation.

Annual sales are thousands of bottles. 6.
value:
6.00 points

Freight car loadings over an 18-week period at a busy port are as follows:

Week Number Week Number Week Number
1 220 7 350 13 500
2 245 8 360 14 475
3 278 9 445 15 510
4 275 10 380 16 510
5 347 11 429 17 502
6 310 12 450 18 541
________________________________________

a. Determine a linear trend line for expected freight car loadings. (Round your intermediate calculations and final answers to 3 decimal places.)

= + t
b. Use the trend equation to predict expected loadings for weeks 22 and 23. (Round your intermediate calculations and final answers to 3 decimal places.)

The forecasted demand for week 22 and 23 is and respectively.

c. The manager intends to install new equipment when the volume exceeds 776 loadings per week. Assuming the current trend continues, the loading volume will reach that level in approximately how many more weeks? (Round your intermediate calculations to 3 decimal places and final answer to the nearest whole number.)

It would take approximately more weeks.7.
value:
6.00 points

a. Obtain the linear trend equation for the following data on new checking accounts at Fair Savings Bank and use it to predict expected new checking accounts for periods 16 through 19. (Round your intermediate calculations and final answers to 2 decimal places.)

Period New Accounts Period New Accounts Period New Accounts
1 200 6 231 11 281
2 219 7 246 12 275
3 211 8 250 13 281
4 225 9 257 14 288
5 235 10 267 15 303
________________________________________

Y =
+ t Y16 =

Y17 =

Y18 =

Y19 =

________________________________________

b. Use trend-adjusted smoothing with a = .2 and ß = .1 to smooth the new account data in part a. What is the forecast for period 16? (Use the “Trend” values to 3 decimal places and other values to 2 decimal places for intermediate calculations. Round your final answer to 2 decimal places.)

Forecast for period 16 8.
value:
6.00 points

After plotting demand for four periods, an emergency room manager has concluded that a trend-adjusted exponential smoothing model is appropriate to predict future demand. The initial estimate of trend is based on the net change of 30 for the three periods from 1 to 4, for an average of +10 units.

Period Actual Period Actual
1 207 6 263
2 229 7 267
3 223 8 289
4 237 9 296
5 253 10
________________________________________

Use a=.5 and ß=.1, and TAF of 250 for period 5. Obtain forecasts for periods 6 through 10. (Round your intermediate calculations and final answers to 2 decimal places.)

t Period TAFt
6 7 8 9 10 ________________________________________
9.
value:
6.00 points

A manager of a store that sells and installs spas wants to prepare a forecast for January, February, and March of next year. Her forecasts are a combination of trend and seasonality. She uses the following equation to estimate the trend component of monthly demand: Ft = 53 + 6t, where t = 0 in June of last year. Seasonal relatives are 1.20 for January, 1.12 for February, and 1.05 for March. What demands should she predict? (Round your answers to 2 decimal places.)

Month Forecast
January of the next year February of the next year March of the next year ________________________________________
10.
value:
6.00 points

The following equation summarizes the trend portion of quarterly sales of condominiums over a long cycle. Sales also exhibit seasonal variations.

Ft = 30 – 5.1t + 3t 2

where
Ft = Unit sales
t = 0 at the first quarter of last year

Quarter Relative
1 1.1
2 1.0
3 .6
4 1.3
________________________________________

Using the information given, prepare a forecast of sales for each quarter of next year (not this year), and the first quarter of the year following that. (Round intermediate calculations and final answers to 2 decimal places.)

Quarter Forecast
1 2 3 4 1 ________________________________________
11.
value:
6.00 points

A tourist center is open on weekends (Friday, Saturday, and Sunday). The owner-manager hopes to improve scheduling of part-time employees by determining seasonal relatives for each of these days. Data on recent traffic at the center have been tabulated and are shown in the following table:

Week
1 2 3 4 5 6
Friday 142 153 152 154 156 163
Saturday 252 257 264 267 271 278
Sunday 167 162 174 173 179 184
________________________________________

a. Develop seasonal relatives for the shop using the centered moving average method. (Round your intermediate calculations and final answers to 2 decimal places.)

Friday Saturday Sunday ________________________________________

b. Develop seasonal relatives for the shop using the SA method. (Round your intermediate calculations and final answers to 4 decimal places.)

SA Index
Friday Saturday Sunday ________________________________________
12.
value:
6.00 points

The manager of a fashionable restaurant open Wednesday through Saturday says that the restaurant does about 26 percent of its business on Friday night, 30 percent on Saturday night, and 24 percent on Thursday night. What seasonal relatives would describe this situation?(Round your answers to 2 decimal places.)

Wednesday Thursday Friday Saturday ________________________________________
13.
value:
6.00 points

Air travel on Mountain Airlines for the past 18 weeks was:

Week Passengers Week Passengers
1 406 10 440
2 410 11 446
3 420 12 451
4 415 13 455
5 412 14 464
6 414 15 466
7 424 16 474
8 433 17 476
9 438 18 469
________________________________________

b. Use an appropriate technique to develop a forecast for the expected number of passengers for the next three weeks. (Round your intermediate calculations to 3 decimal places and final answers to 2 decimal places.)

Week Forecasted demand
19 20 21 ________________________________________
14.
value:
6.00 points

A pharmacist has been monitoring sales of a certain over-the-counter pain reliever. Daily sales during the last 15 days were

Day: 1 2 3 4 5 6 7 8 9
Number sold: 36 38 42 44 48 49 50 49 52
Day: 10 11 12 13 14 15
Number sold: 48 53 55 54 56 57
________________________________________

a. Assume that the data refer to demand rather than sales. Using trend-adjusted smoothing with an initial forecast of 51 for week 8, an initial trend estimate of 4, and a = ß = .2, develop forecasts for days 9 through 16. What is the MSE for the 8 forecasts for which there are actual data? (Round your intermediate calculations and final answer to 3 decimal places.)

MSE
b. If the pharmacist learns that on some days the store ran out of the specific pain reliever, should she be concerned?

15.
value:
6.00 points

New car sales for a dealer in Cook County, Illinois, for the past year are shown in the following table, along with monthly indexes (seasonal relatives), which are supplied to the dealer by the regional distributor.

Month Units Sold Index Month Units Sold Index
Jan. 648 0.70 Jul. 762 0.90
Feb. 648 0.80 Aug. 814 1.10
Mar. 628 0.60 Sept. 838 1.20
Apr. 704 0.94 Oct. 837 1.20
May 725 0.89 Nov. 840 1.20
Jun. 809 1.00 Dec. 790 1.25
________________________________________

b. Deseasonalize car sales. (Round your answers to the nearest whole number.)

Month Deseasonalized Month Deseasonalized
Jan.
Jul. Feb.
Aug. Mar.
Sep. Apr.
Oct. May
Nov. Jun.
Dec. ________________________________________

e. What action might management consider based on your findings in part b?

Advertising and sales promotions

Improve the model

Cost reduction

Increase inventory

16.
value:
6.00 points

The following table shows a tool and die company’s quarterly sales for the current year. What sales would you predict for the first quarter of next year? Quarter relatives are SR1= 1.10, SR2 = .99, SR3 = .90, and SR4 = 1.01.

Quarter 1 2 3 4
Sales 66 79.2 90.0 121.2
________________________________________

Forecast 17.
value:
6.00 points

An analyst must decide between two different forecasting techniques for weekly sales of roller blades: a linear trend equation and the naive approach. The linear trend equation is Ft = 123 + 2.0t, and it was developed using data from periods 1 through 10. Based on data for periods 11 through 20 as shown in the table, which of these two methods has the greater accuracy if MAD and MSE are used? (Round your answers to 2 decimal places.)

t Units Sold
11 146
12 148
13 150
14 142
15 156
16 150
17 156
18 157
19 159
20 163
________________________________________

MAD (Naive) MAD (Linear) MSE (Naive) MSE (Linear) ________________________________________

provides forecasts with less average error and less average squared error.
Portfolio 2 Part 2 (chapter 5)
1.
value:
3.00 points

Determine the utilization and the efficiency for each of these situations:

a. A loan processing operation that processes an average of 4 loans per day. The operation has a design capacity of 16 loans per day and an effective capacity of 14 loans per day. (Round your answer to 1 decimal place. Omit the “%” sign in your response.)

Utilization % Efficiency %
b. A furnace repair team that services an average of 2 furnaces a day if the design capacity is 8 furnaces a day and the effective capacity is 7 furnaces a day. (Round your answer to 1 decimal place. Omit the “%” sign in your response.)

Utilization % Efficiency %
c. Would you say that systems that have higher efficiency ratios than other systems will always have higher utilization ratios than those other systems?

This is not necessarily . If the design capacity is relatively , the utilization could be even though the efficiency was .

2.
value:
3.00 points

In a job shop, effective capacity is only 88 percent of design capacity, and actual output is 66 percent of effective output. What design capacity would be needed to achieve an actual output of 20 jobs per week?(Round your answer to the nearest whole number.)

Design capacity jobs 3.
value:
3.00 points

A producer of pottery is considering the addition of a new plant to absorb the backlog of demand that now exists. The primary location being considered will have fixed costs of $8,288 per month and variable costs of 67 cents per unit produced. Each item is sold to retailers at a price that averages 93 cents.

a. What volume per month is required in order to break even? (Round your answer to the nearest whole number.)

Volume per month units
b-1. What profit would be realized on a monthly volume of 74,892 units? (Round your answer to the nearest dollar amount. Omit the “$” sign in your response.)

Profit $
b-2. What profit would be realized on a monthly volume of 85,544 units? (Round your answer to the nearest dollar amount. Omit the “$” sign in your response.)

Profit $
c. What volume is needed to obtain a profit of $12,774 per month? (Round your answer to the nearest whole number.)

Volume per month units
d. What volume is needed to provide a revenue of $30,960 per month? (Round your answer to the nearest whole number.)

Volume per month units 4.
value:
3.00 points

A small firm intends to increase the capacity of a bottleneck operation by adding a new machine. Two alternatives, A and B, have been identified, and the associated costs and revenues have been estimated. Annual fixed costs would be $36,000 for A and $35,000 for B; variable costs per unit would be $10 for A and $11 for B; and revenue per unit would be $19.

a. Determine each alternative’s break-even point in units. (Round your answer to the nearest whole amount.)

QBEP,A units QBEP,B units
b. At what volume of output would the two alternatives yield the same profit? (Round your answer to thenearest whole amount.)

Profit units
c. If expected annual demand is 18,000 units, which alternative would yield the higher profit?

Higher profit 5.
value:
3.00 points

A producer of felt-tip pens has received a forecast of demand of 49,000 pens for the coming month from its marketing department. Fixed costs of $27,000 per month are allocated to the felt-tip operation, and variable costs are 28 cents per pen.

a. Find the break-even quantity if pens sell for $1 each. (Round your answer to the next whole number.)

QBEP units
b. At what price must pens be sold to obtain a monthly profit of $18,000, assuming that estimated demand materializes? (Round your answer to 2 decimal places. Omit the “$” sign in your response.)

Price $ 6.
value:
3.00 points

A real estate agent is considering changing her cell phone plan. There are three plans to choose from, all of which involve a monthly service charge of $26. Plan A has a cost of $0.48 a minute for daytime calls and $0.25 a minute for evening calls. Plan B has a charge of $0.51 a minute for daytime calls and $0.13 a minute for evening calls. Plan C has a flat rate of $96 with 234 minutes of calls allowed per month and a charge of $.40 per minute beyond that, day or evening.

a. Determine the total charge under each plan for this case: 150 minutes of day calls and 39 minutes of evening calls in a month. (Round your answer to the nearest whole number. Omit the “$” sign in your response.)

Cost for Plan A $ Cost for Plan B $ Cost for Plan C $

c. If the agent will use the service for daytime calls, over what range of call minutes will each plan be optimal? (Round your answer to the nearest whole number.)

Plan A is optimal for zero to less than minutes. Plan C is optimal from minutes or more.

d. Suppose that the agent expects both daytime and evening calls. At what point (i.e., percentage of call minutes for daytime calls) would she be indifferent between plans A and B? (Round your answer to the nearest whole percent. Omit the “%” sign in your response.)

Point percent daytime minutes 7.
value:
3.00 points

A firm plans to begin production of a new small appliance. The manager must decide whether to purchase the motors for the appliance from a vendor at $7 each or to produce them in-house. Either of two processes could be used for in-house production; one would have an annual fixed cost of $162,306 and a variable cost of $5 per unit, and the other would have an annual fixed cost of $193,372 and a variable cost of $4 per unit. Determine the range of annual volume for which each of the alternatives would be best. (Round your answer to the nearest whole number.)

For annual volume less than , is best. For larger quantities, best to produce in house at $ per unit.

8.
value:
3.00 points

A company manufactures a product using two machine cells. Each cell has a design capacity of 250 units per day and an effective capacity of 230 units per day. At present, actual output averages 200 units per cell, but the manager estimates that productivity improvements soon will increase output to 223 units per day. Annual demand is currently 60,000 units. It is forecasted that within two years, annual demand will triple. How many cells should the company plan to produce to satisfy predicted demand under these conditions? Assume 236 workdays per year. (Round up your answer to the next whole number.)

Cells 9.
value:
3.00 points

A manager must decide which type of machine to buy, A, B, or C. Machine costs are as follows:

Machine Cost
A $ 47,172
B $ 27,644
C $ 83,843
________________________________________

Product forecasts and processing times on the machines are as follows:

PROCCESSING TIME PER UNIT (minutes)
Product Annual
Demand A B C
1 17,462 3 4 2
2 11,876 4 4 3
3 5,387 5 6 4
4 29,066 2 2 1
________________________________________
a. Assume that only purchasing costs are being considered. Which machine would have the lowest total cost, and how many of that machine would be needed? Machines operate 10 hours a day, 250 days a year. (Round up your answers to the next whole number.)

Total processing time in minutes per machine:
A B C ________________________________________

Number of each machine needed and total cost
A
$ B
$ C
$ Buy machines.________________________________________

b. Consider this additional information: The machines differ in terms of hourly operating costs: The A machines have an hourly operating cost of $12 each, B machines have an hourly operating cost of $10 each, and C machines have an hourly operating cost of $15 each. Which alternative would be selected, and how many machines, in order to minimize total cost while satisfying capacity processing requirements? (Round your answers to the nearest whole number.)

Total cost for each machine
A B C Buy machines.________________________________________
10.
value:
3.00 points

A manager must decide how many machines of a certain type to purchase. Each machine can process 100 customers per day. One machine will result in a fixed cost of $2,000 per day, while two machines will result in a fixed cost of $3,800 per day. Variable costs will be $19 per customer, and revenue will be $45 per customer.

a. Determine the break-even point for each range. (Round your answers to the next whole number.)

One machine Two machines
b. If estimated demand is 90 to 120 customers per day, how many machines should be purchased?

11.
value:
3.00 points

The manager of a car wash must decide whether to have one or two wash lines. One line will mean a fixed cost of $5,800 a month, and two lines will mean a fixed cost of $8,700 a month. Each line would be able to process 15 cars an hour. Variable costs will be $3 per car, and revenue will be $5.95 per car. The manager projects an average demand of between 14 and 18 cars an hour. Would you recommend one or two lines? The car wash is open 290 hours a month.

Choose line.12.
value:
3.00 points

The following diagram shows a 4-step process that begins with Operation 1 and ends with Operation 4. The rates shown in each box represent the effective capacity of that operation.
Determine the capacity of this process.

Capacity /hr 13.
value:
4.00 points

The following diagram describes a process that consists of eight separate operations, with sequential relationships and capacities (units per hour) as shown.

a. What is the current capacity of the entire process?

Capacity units per hour
b-1. If you could increase the capacity of only two operations through process improvement efforts, which two operations would you select, how much additional capacity would you strive for in each of those operations? (Enter your answers as whole numbers. Enter the lower operation number in the TOP answer box and the higher operation number in the BOTTOM answer box.)

Operations Additional capacity

________________________________________

b-2. What would the resulting capacity of the entire process be?

Resulting capacity units per hour
Portfolio 2 Part 3 (chapter 6)
1.
value:
3.00 points

An assembly line with 17 tasks is to be balanced. The longest task is 2.4 minutes, and the total time for all tasks is 18 minutes. The line will operate for 450 minutes per day.

a. What are the minimum and maximum cycle times? (Round your answers to 1 decimal place.)
Minimum cycle time minutes Maximum cycle time minutes ________________________________________

b. What range of daily output is theoretically possible for the line? (Round your answers to 1 decimal place. Enter the smaller value in the first box and the larger value in the second box.)

Range of output to units/day
c. What is the minimum number of workstations needed if the maximum output rate is to be sought?(Round your answer to the next whole number.)

Minimum number of workstations
d. What cycle time will provide an output rate of 125 units per day? (Round your answer to 1 decimal place.)

Cycle time min/cycle
e. What output potential will result if the cycle time is (1) 9 minutes? (2) 15 minutes?

Cycle Time Potential Output
(1) units (2) units ________________________________________
2.
value:
3.00 points

A producer of inkjet printers is planning to add a new line of printers, and you have been asked to balance the process, given the following task times and precedence relationships. Assume that cycle time is to be the minimum possible.

Task Length
(minutes) Immediate
Predecessor
a 0.2 –
b 0.4 a
c 0.3 –
d 1.3 b, c
e 0.1 –
f 0.8 e
g 0.3 d, f
h 1.2 g
________________________________________

a. Do each of the following:

(2) Assign tasks to stations in order of greatest number of following tasks.

Work Station Task Assigned
I II III IV ________________________________________

Task Following
Tasks
a b c d e f g h ________________________________________

(3) Determine the percentage of idle time. (Round your answer to 2 decimal places. Omit the “%” sign in your response.)

Percentage of idle time %
(4) Compute the rate of output in printers per day that could be expected for this line assuming a 420-minute working day. (Round your answer to the nearest whole number.)

Rate of output units per day
b. Answer these questions:

(1) What is the shortest cycle time that will permit use of only two workstations? (Round your answer to 1 decimal place.)

Shortest cycle time minutes
(2) Determine the percentage of idle time that would result if two stations were used and each station was loaded with the worktime shown in Part b(1). (Leave no cells blank – be certain to enter “0” wherever required. Omit the “%” sign in your response.)

Percentage of idle time %
(3) What is the daily output under this arrangement using the operating time from Part a(4)? (Round your answer to 1 decimal place.)

Daily output units per day
(4) Determine the output rate that would be associated with the maximum cycle time using the operating time from Part a(4). (Round your answer to 2 decimal places.)

Rate of output units per day 3.
value:
4.00 points

As part of a major plant renovation project, the industrial engineering department has been asked to balance a revised assembly operation to achieve an output of 240 units per eight-hour day. Task times and precedence relationships are as follows:

Task Duration
(minutes) Immediate
Predecessor
a 0.2 –
b 0.4 a
c 0.2 b
d 0.4 –
e 1.2 d
f 1.2 c
g 1.0 e, f
________________________________________

Do each of the following:

b. Determine the minimum cycle time, the maximum cycle time, and the calculated cycle time.(Round your answers to 1 decimal place.)

The minimum cycle time minutes The maximum cycle time minutes Calculated cycle time minutes ________________________________________

c. Determine the minimum number of stations needed. (Round your answer to the next whole number.)

Minimum number of stations
d. Assign tasks to workstations on the basis of greatest number of following tasks. Use longest processing time as a tiebreaker. If ties still exist, assume indifference in choice.

Work stations Following Tasks
I II III IV ________________________________________

e. Compute the percentage of idle time for the assignment in part d. Use the actual bottleneck cycle time in your calculation. (Round your answer to 1 decimal place. Omit the “%” sign in your response.)

Percentage of idle time %
Portfolio 2 Part 4 (chapter 7)
1.
value:
4.00 points

An analyst has timed a metal-cutting operation for 50 cycles. The average time per cycle was 10.8 minutes, and the standard deviation was 1.20 minutes for a worker with a performance rating of 129 percent. Assume an allowance of 10 percent of job time. Find the standard time for this operation. (Do not round intermediate calculations. Round your final answer to 2 decimal places.)

Standard time minutes 2.
value:
4.00 points

A job was timed for 60 cycles and had an average of 2.4 minutes per piece. The performance rating was 92 percent, and workday allowances are 19 percent. Determine each of the following:

a. Observed time. (Round your answer to 1 decimal place.)

Observed time minutes
b. Normal time. (Round your answer to 2 decimal places.)

Normal time minutes
c. Standard time. (Round your answer to 2 decimal places.)

Standard time minutes 3.
value:
4.00 points

A time study was conducted on a job that contains four elements. The observed times and performance ratings for six cycles are shown in the following table.

OBSERVATIONS (minutes per cycle)
Element Performance
Rating 1 2 3 4 5 6
1 90% 0.44 0.50 0.43 0.45 0.42 0.46
2 85 1.50 1.53 1.47 1.51 1.49 1.52
3 110 0.84 0.89 0.77 0.83 0.88 0.80
4 100 1.10 1.14 1.08 1.18 1.16 1.26
________________________________________

a. Determine the average cycle time for each element. (Round your answers to 3 decimal places.)

Element Average cycle
1 2 3 4 ________________________________________

b. Find the normal time for each element. (Round your answers to 3 decimal places.)

Element Normal time
1 2 3 4 ________________________________________

c. Assuming an allowance factor of 17 percent of job time, compute the standard time for this job. (Round your answers to 3 decimal places.)

Element Standard time
1 2 3 4 ________________________________________
4.
value:
4.00 points

Given these observed times (in minutes) for four elements of a job, determine the observed time (OT) for each element. Note: The second element only occurs every other cycle. (Round your answers to 2 decimal places.)

CYCLE
Element 1 2 3 4 5 6
1 4.1 4.0 4.7 4.1 4.1 4.1
2 – 1.5 – 2.0 – 1.4
3 3.2 3.2 3.6 3.2 3.3 3.3
4 2.7 3.6 2.7 2.8 2.8 2.8
________________________________________

Element Observed Time
1 2 3 4 ________________________________________
5.
value:
4.00 points

Given these observed times (in minutes) for five elements of a job, determine the observed time (OT) for each element. Note: Some of the elements occur only periodically. (Round your answers to 2 decimal places.)

CYCLE
Element 1 2 3 4 5 6
1 2.1 2.0 2.8 2.1 2.1 –
2 – 1.5 – 1.0 – 1.2
3 3.4 3.5 3.3 4.4 3.4 3.3
4 4.0 – – 5.1 – –
5 1.4 1.4 1.7 1.5 1.5 1.4
________________________________________

Element Observed Time
1 2 3 4 5 ________________________________________
6.
value:
4.00 points

Using the following data, develop an allowance percentage for a job element that requires the worker to lift a weight of 25 pounds while (1) standing in a slightly awkward position, (2) in light that is slightly below recommended standards, and (3) with intermittent loud noises occurring. The monotony for this element is low. Include a personal allowance of 5 percent and a basic fatigue allowance of 4 percent of job time.(Leave no cells blank – be certain to enter “0” wherever required. Omit the “%” sign in your response.)

Percent Percent
A. Constant allowances: 4. Bad light:
1. Personal allowance 5 a. Slightly below recommended 0
2. Basic fatigue allowances 4 b. Well below 2
B. Variable allowances: c. Very inadequate 5
1. Standing allowance 2 5. Atmospheric conditions
2. Abnormal position allowance: (heat and humidity)—variable 0-10
a. Slightly awkward 0 6. Close attention:
b. Awkward (bending) 2 a. Fairly fine work 0
c. Very awkward (lying, stretching) 7 b. Fine or exacting 2
3. Use of force or muscular energy c. Very fine or very exacting 5
(lifting, pulling, or pushing): 7. Noise level:
Weight lifted (in pounds): a. Continuous 0
5 0 b. Intermittent—loud 2
10 1 c. Intermittent—very loud 5
15 2 d. High-pitched—loud 5
20 3 8. Mental strain:
25 4 a. Fairly complex process 1
30 5 b. Complex or wide span of attention 4
35 7 c. Very complex 8
40 9 9. Monotony:
45 11 a. Low 0
50 13 b. Medium 1
60 17 c. High 4
70 22 10. Tediousness:
a. Rather tedious 0
b. Tedious 2
c. Very tedious 5
________________________________________

Factor %
Personal Fatigue Standing Lifting Bad Light Noise Level Monotony ________________________________________
Total ________________________________________________________________________________
________________________________________
7.
value:
4.00 points

A worker-machine operation was found to involve 4.2 minutes of machine time per cycle in the course of 40 cycles of stopwatch study. The worker’s time averaged 1.6 minutes per cycle, and the worker was given a rating of 120 percent (machine rating is 100 percent). Midway through the study, the worker took a 10-minute rest break. Assuming an allowance factor of 12 percent of work time, determine the standard time for this job. (Do not round intermediate calculations. Round your final answer to 2 decimal places.)

Standard time minutes 8.
value:
4.00 points

The data in the table below represent time study observations for a woodworking operation. (Hint: See Solved Problems section.)

OBSERVATIONS (minutes per cycle)
Element Performance
Rating 1 2 3 4 5 6
1 110% 1.20 1.13 1.16 1.22 1.24 1.15
2 115 0.83 0.87 .76 0.82 0.85 1.32*
3 105 0.58 0.53 0.52 .55 0.60 0.54
________________________________________

*Unusual delay, disregard time.

a. Based on the observations, determine the standard time for the operation, assuming an allowance of 18 percent of job time. (Round your intermediate calculations and final answers to 3 decimal places.)

Element Standard time
1 2 3 ________________________________________

b. How many observations would be needed to estimate the mean time for element 2 within 3 percent of its true value with a 95.5 percent confidence? (Round your intermediate calculations to 3 decimal places and round up your final answer to the next whole number.)

Number of observations
c. How many observations would be needed to estimate the mean time for element 2 within .01 minute of its true value with a 95.5 percent confidence? (Round your intermediate calculations to 3 decimal places and round up your final answer to the next whole number.)

Number of observations
9.
value:
4.00 points

How many observations should a time study analyst plan for in an operation that has a standard deviation of 1.2 minutes per piece if the goal is to estimate the mean time per piece to within .5 minute with a confidence of 95.5 percent? (Do not round intermediate calculations. Round up your final answer to the next whole number.)

Number of observations 10.
value:
4.00 points

How many work cycles should be timed to estimate the average cycle time to within 2 percent of the sample mean with a confidence of 99 percent if a pilot study yielded these times (minutes): 5.2, 5.5, 6.8, 5.3, 5.5, and 5.1? The standard deviation is .625 minutes per cycle. (Use the “mean time” value to 2 decimal places and other values to 3 decimal places for intermediate calculations. Round up your final answer to the next whole number.)

Number of work cycles 11.
value:
5.00 points

In an initial survey designed to estimate the percentage of time air-express cargo loaders are idle, an analyst found that loaders were idle in 3 of the 50 observations.

a. What is the estimated percentage of idle time? (Omit the “%” sign in your response.)

Estimated percentage of idle time %
b. Based on the initial results, approximately how many observations would you require to estimate the actual percentage of idle time to within 7 percent with a confidence of 95 percent? (Do not round intermediate calculations. Round up your final answer to the next whole number.)

Number of observations 12.
value:
5.00 points

A job in an insurance office involves telephone conversations with policyholders. The office manager estimates that about half of the employee’s time is spent on the telephone. How many observations are needed in a work sampling study to estimate that time percentage to within 7 percent and have a confidence of 98 percent? (Do not round intermediate calculations. Round your final answer to the nearest whole number.)

Number of observations
Portfolio 2 Part 5 (chapter 8)
1.
value:
3.00 points

A newly formed firm must decide on a plant location. There are two alternatives under consideration: locate near the major raw materials or locate near the major customers. Locating near the raw materials will result in lower fixed and variable costs than locating near the market, but the owners believe there would be a loss in sales volume because customers tend to favor local suppliers. Revenue per unit will be $181 in either case.

Omaha Kansas City
Annual fixed costs ($ millions) $ 0.9 $ 1.4
Variable cost per unit $ 31 $ 46
Expected annual demand (units) 9,450 10,650
________________________________________

Using the above information, determine which location would produce the greater profit. (Omit the “$” sign in your response.)

would produce the greater gross profit of $ .2.
value:
3.00 points

The owner of Genuine Subs, Inc., hopes to expand the present operation by adding one new outlet. She has studied three locations. Each would have the same labor and materials costs (food, serving containers, napkins, etc.) of $1.70 cents per sandwich. Sandwiches sell for $2.69 each in all locations. Rent and equipment costs would be $5,070 per month for location A, $5,590 per month for location B, and $5,730 per month for location C.

a. Determine the volume necessary at each location to realize a monthly profit of $9,500. (Do not round intermediate calculations. Round your answer to the nearest whole number.)

Location Volume
A B C ________________________________________

b-1. If expected sales at A, B, and C are 20,400 per month, 23,000 per month, and 22,600 per month, respectively, calculate the profit of the each locations? (Omit the “$” sign in your response.)

Location Profits
A $ B $ C $ ________________________________________

b-2. Which location would yield the greatest profits?

Location A

Location C

Location B

3.
value:
3.00 points

A small producer of machine tools wants to move to a larger building, and has identified two alternatives. Location A has annual fixed costs of $130,000 and variable costs of $10,000 per unit; location B has annual fixed costs of $330,000 and variable costs of $8,000 per unit. The finished items sell for $12,000 each.

a. At what volume of output would the two locations have the same total cost?

Volume of output units
b-1. For what range of output would location A be superior?

Range of output 0 to
b-2. For what range would B be superior?

Range of output or more 4.
value:
3.00 points

A company that produces pleasure boats has decided to expand one of its lines. Current facilities are insufficient to handle the increased workload, so the company is considering three alternatives, A (new location), B (subcontract), and C (expand existing facilities).
Alternative A would involve substantial fixed costs but relatively low variable costs: fixed costs would be $275,000 per year, and variable costs would be $590 per boat. Subcontracting would involve a cost per boat of $2,600, and expansion would require an annual fixed cost of $60,000 and a variable cost of $1,100 per boat.

a. Find the range of output for each alternative that would yield the lowest total cost. (Leave no cells blank – be certain to enter “0” wherever required. Round your answers to the nearest whole number.)
A
or more
B
to C
to ________________________________________

b. Which alternative would yield the lowest total cost for an expected annual volume of 290 boats?

5.
value:
3.00 points

A firm that has recently experienced an enormous growth rate is seeking to lease a small plant in Memphis, TN; Biloxi, MS; or Birmingham, AL. Prepare an economic analysis of the three locations given the following information: Annual costs for building, equipment, and administration would be $40,600 for Memphis, $60,000 for Biloxi, and $100,000 for Birmingham. Labor and materials are expected to be $8 per unit in Memphis, $4 per unit in Biloxi, and $5 per unit in Birmingham. The Memphis location would increase system transportation costs by $50,000 per year, the Biloxi location by $60,000 per year, and the Birmingham location by $29,400 per year. Expected annual volume is 13,000 units.(Omit the “$” sign in your response.)

Total Cost
Memphis $ Biloxi $ Birmingham $ ________________________________________
6.
value:
3.00 points

A retired auto mechanic hopes to open a rustproofing shop. Customers would be local new-car dealers. Two locations are being considered, one in the center of the city and one on the outskirts. The central city location would involve fixed monthly costs of $6,970 and labor, materials, and transportation costs of $30 per car. The outside location would have fixed monthly costs of $4,300 and labor, materials, and transportation costs of $40 per car. Dealer price at either location will be $90 per car.

a. Which location will yield the greatest profit if monthly demand is (1) 200 cars? (2) 300 cars?

200 cars: yields the greatest profit.
300 cars: yields the greatest profit.

b. At what volume of output will the two sites yield the same monthly profit?

Volume of output cars 7.
value:
3.00 points

Location Score
Factor
(100 points each) Weight A B C
Convenience .15 86 77 83
Parking facilities .20 70 88 98
Display area .18 86 90 94
Shopper traffic .27 90 88 89
Operating costs .10 86 91 96
Neighborhood .10 90 86 84
________________________________________
1.00
________________________________________________________________________________
________________________________________

a. Using the above factor ratings, calculate the composite score for each location. (Do not round intermediate calculations. Round your final answers to 2 decimal places.)

Location Composite Score
A B C ________________________________________

b. Determine which location alternative (A, B, or C) should be chosen on the basis of maximum composite score.

8.
value:
3.00 points

Factor Weight East #1 East #2 West
Initial cost 10 160 120 160
Traffic 10 40 55 60
Maintenance 5 25 25 25
Dock space 6 22 19 22
Neighborhood 3 9 7 8
________________________________________

a. Using the above factor ratings, calculate the composite score for each location.

Location Composite Score
East #1 East #2 West ________________________________________

b. Determine which location has the highest composite score:

East #2

West

East #2

9.
value:
3.00 points

A manager has received an analysis of several cities being considered for a new office complex. The data (10 points maximum) are as follows:

Location Score
Factor A B C
Business services 8 5 5
Community services 7 6 7
Real estate cost 3 8 7
Construction costs 5 7 6
Cost of living 3 8 9
Taxes 5 5 4
Transportation 6 7 8
________________________________________

a. If the manager weights the factors equally, how would the locations stack up in terms of their composite factor rating scores?
A / 7 B / 7 C / 7 ________________________________________

Thus, is the best.
b. If business services and construction costs are given weights that are double the weights of the other factors, how would the locations stack up?
A / 9 B / 9 C / 9 ________________________________________

Thus, is best and is least desirable.
10.
value:
3.00 points

A toy manufacturer produces toys in five locations throughout the country. Raw materials (primarily barrels of powdered plastic) will be shipped from a new, centralized warehouse whose location is to be determined. The monthly quantities to be shipped to each location are the same. A coordinate system has been established, and the coordinates of each location have been determined as shown. Determine the coordinates of the centralized warehouse. (Round and to 1 decimal place and optimal points to the nearest whole number.)

Location (x,y)
A 7,7
B 8,3
C 5,6
D 4,1
E 6,4
________________________________________

= , = : Thus, location optimal at ( , ).11.
value:
3.00 points

A clothing manufacturer produces women’s clothes at four locations in Mexico. Relative locations have been determined, as shown in the table below. The location of a central shipping point for bolts of cloth must now be determined. Weekly quantities to be shipped to each location are also shown in the table. Determine the coordinates of the location that will minimize distribution costs. (Round and to 1 decimal place and optimal points to the nearest whole number.)

Location (x,y) Weekly Quantity
A 3,7 15
B 6,8 20
C 3,9 25
D 9,7 30
________________________________________

= , = : Thus, location optimal at ( , ).12.
value:
3.00 points

A company that handles hazardous waste wants to minimize the shipping cost for shipments to a disposal center from five receiving stations it operates. Given the locations of the receiving stations and the volumes to be shipped daily, determine the location of the disposal center. (Round and to 2 decimal places and optimal points to the nearest whole number.)

Location of Processing Station, (x, y) Volume,
Tons per Day
7,5 26
4,2 9
5,7 25
2,9 30
7,7 40
________________________________________

= , = : Thus, location optimal at ( , ).13.
value:
4.00 points

An analysis of sites for a distribution center has led to two possible sites (L1 and L2 on the map). The sites are comparable on every key factor. The one remaining factor is the center of gravity. Use the center of gravity method to select the better site. Monthly shipments will be the quantities listed in the table. (Round your answers to 2 decimal places.)
Destination Quantity
D1 780
D2 450
D3 525
D4 690
D5 850
________________________________________

x
y
Portfolio 3 Part 1 (chapter 9)
[The following information applies to the questions displayed below.]

The following are the car repair shop data:

Ticket No. Work Ticket No. Work Ticket No. Work
1 Tires 11 Brakes 21 Lube & oil
2 Brakes 12 Battery 22 Battery
3 Tires 13 Brakes 23 Brakes
4 Lube & oil 14 Lube & oil 24 Lube & oil
5 Tires 15 Brakes 25 Lube & oil
6 Transmission 16 Lube & oil 26 Tires
7 Battery 17 Transmission 27 Lube & oil
8 Brakes 18 Lube & oil 28 Tires
9 Tires 19 Tires 29 Lube & oil
10 Lube & oil 20 Brakes 30 Lube & oil
________________________________________
1.
value:
3.00 points

a. Prepare a check sheet for the above car repair shop data:

Work Type Frequency
Lube & oil Brakes Tires Battery Transmission ________________________________________
Total ________________________________________________________________________________
________________________________________

rev: 03_15_2012
View Hint #1
2.
value:
2.00 points

b. Select a appropriate Pareto diagram for the above car repair shop data:

[The following information applies to the questions displayed below.]
An air-conditioning repair department manager has compiled data on the primary reason for 41 service calls for the previous week, as shown in the table.

Job
Number Problem/
Customer Type Job
Number Problem/
Customer Type Job
Number Problem/
Customer Type
301 O/R 315 N/R 329 W/R
302 W/C 316 N/R 330 W/R
303 N/R 317 W/C 331 O/R
304 N/R 318 N/R 332 F/R
305 F/R 319 W/C 333 N/R
306 W/R 320 O/R 334 O/C
307 F/R 321 F/C 335 F/C
308 O/C 322 O/R 336 N/R
309 F/C 323 N/R 337 N/R
310 O/C 324 O/R 338 N/R
311 F/R 325 N/R 339 N/R
312 F/R 326 W/R 340 O/C
313 N/C 327 W/C 341 N/R
314 F/R 328 F/R
________________________________________

Key: Problem type: Customer type:
N = Noisy C = Commercial customer
F = Equipment failure R = Residential customer
W = Runs warm
O = Odor
________________________________________
3.
value:
3.00 points

a. Using the data, prepare a check sheet for the problem types for each customer type.

(1) Residential customer type

Residential
Noisy Failed Odor Warm ________________________________________
Totals ________________________________________________________________________________
________________________________________

(2) Commercial customer type

Commercial
Failed Noisy Odor Warm ________________________________________
Totals ________________________________________________________________________________
________________________________________

rev: 03_15_2012
View Hint #1
4.
value:
3.00 points

b. Select a appropriate Pareto diagram for the Residential customers.

View Hint #1

5.
value:
3.00 points

c. Select a appropriate Pareto diagram for the Commercial customers.

6.
value:
3.00 points

Choose the correct run chart for the occurrences of defective computer monitors based on the following data, which an analyst obtained from the process for making the monitors. Workers are given a 15-minute break at 10:15 a.m. and 3:15 p.m., and a lunch break at noon.

Interval Start
Time Number of Defects Interval Start Time Number of Defects Interval Start Time Number of Defects
8:00 0 10:45 0 2:15 0
8:15 0 11:00 0 2:30 2
8:30 0 11:15 1 2:45 1
8:45 0 11:30 0 3:00 3
9:00 1 11:45 2 3:30 0
9:15 0 1:00 0 3:45 0
9:30 0 1:15 0 4:00 0
9:45 1 1:30 1 4:15 0
10:00 2 1:45 0 4:30 1
10:30 1 2:00 0 4:45 2
________________________________________

7.
value:
3.00 points

Choose the correct scatter diagram for each of these data sets. Put the first variable on the horizontal axis and the second variable on the vertical axis.
a.
Age 24 30 22 25 33 27 36 58 37 47 54 28 42 55
Absenteeism rate 8 6 8 7 5 6 4 1 3 2 2 5 3 1
________________________________________

I. II.

III. IV.

The correct graph is under the number .
b.
Temperature (ºF) 65 63 72 66 82 58 75 86 77 65 79
Error rate 3 4 1 1 5 5 2 6 3 2 4
________________________________________

I. II.

III. IV.

The correct graph is under the number .
Portfolio 3 Part 2 (chapter 10)
1.
value:
5.00 points

An automatic filling machine is used to fill 1-liter bottles of cola. The machine’s output is approximately normal with a mean of .97 liter and a standard deviation of .03 liter. Output is monitored using means of samples of 26 observations. Use Table-A.
a. Determine upper and lower control limits that will include roughly 97 percent of the sample means when the process is in control. (Do not round intermediate calculations. Round your answers to 4 decimal places.)
Upper control limits: liter Lower control limits: liter ________________________________________

b. Given these sample means: 1.005, 1.001, .998, 1.002, .995, and .999, is the process in control?

Yes

2.
value:
5.00 points

Checkout time at a supermarket is monitored using a mean and a range chart. Six samples of n = 20 observations have been obtained and the sample means and ranges computed:

Sample Mean Range Sample Mean Range
1 3.06 .42 4 3.13 .46
2 3.15 .51 5 3.06 .46
3 3.11 .41 6 3.09 .45
________________________________________

Factors for three-sigma control limits for and R charts

FACTORS FOR R CHARTS
Number of Observations in Subgroup,
n Factor for
Chart,
A2 Lower
Control Limit,
D3 Upper
Control Limit,
D4
2 1.88 0 3.27
3 1.02 0 2.57
4 0.73 0 2.28
5 0.58 0 2.11
6 0.48 0 2.00
7 0.42 0.08 1.92
8 0.37 0.14 1.86
9 0.34 0.18 1.82
10 0.31 0.22 1.78
11 0.29 0.26 1.74
12 0.27 0.28 1.72
13 0.25 0.31 1.69
14 0.24 0.33 1.67
15 0.22 0.35 1.65
16 0.21 0.36 1.64
17 0.20 0.38 1.62
18 0.19 0.39 1.61
19 0.19 0.40 1.60
20 0.18 0.41 1.59
________________________________________

a. Using the factors in the above table, determine upper and lower limits for mean and range charts.(Round your intermediate calculations and final answers to 4 decimal places.)
Upper limit for mean Lower limit for mean Upper limit for range Lower limit for range ________________________________________

b. Is the process in control?

Yes

3.
value:
6.00 points

Computer upgrades have a nominal time of 80 minutes. Samples of five observations each have been taken, and the results are as listed.

SAMPLE
1 2 3 4 5 6
79.2 80.5 79.6 78.9 80.5 79.7
78.8 78.7 79.6 79.4 79.6 80.6
80.0 81.0 80.4 79.7 80.4 80.5
78.4 80.4 80.3 79.4 80.8 80.0
80.7 80.1 80.8 80.6 78.8 81.1
________________________________________

Factors for three-sigma control limits for and R charts

a. Using factors from above table, determine upper and lower control limits for mean and range charts.(Round your intermediate calculations and final answers to 2 decimal places. Leave no cells blank – be certain to enter “0” wherever required.)

Mean Chart Range Chart
UCL
LCL
________________________________________

b. Decide if the process is in control.

Yes

4.
value:
6.00 points

A medical facility does MRIs for sports injuries. Occasionally a test yields inconclusive results and must be repeated. Using the following sample data and n = 194.

SAMPLE
1 2 3 4 5 6 7 8 9 10 11 12 13
Number of retests 1 1 1 0 1 2 2 0 1 8 4 1 2
________________________________________

a. Determine the upper and lower control limits for the fraction of retests using two-sigma limits. (Do not round intermediate calculations. Round your final answers to 4 decimal places. Leave no cells blank – be certain to enter “0” wherever required.)
UCL LCL ________________________________________

b. Is the process in control?

Yes

5.
value:
6.00 points

The postmaster of a small western town receives a certain number of complaints each day about mail delivery.

DAY
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Number of complaints 4 12 16 8 9 6 5 12 15 7 6 4 2 9
________________________________________

a. Determine two-sigma control limits using the above data. (Round your intermediate calculations to 4 decimal places and final answers to 3 decimal places. Leave no cells blank – be certain to enter “0” wherever required.)
UCL LCL ________________________________________

b. Is the process in control?

Yes

6.
value:
6.00 points

Given the following data for the number of defects per spool of cable.

OBSERVATION
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Number of defects 3 5 1 0 1 4 1 0 2 4 3 1 2 0
________________________________________

a. Determine three-sigma control limits using the above data. (Do not round intermediate calculations. Round your final answers to 2 decimal places. Leave no cells blank – be certain to enter “0” wherever required.)
UCL LCL ________________________________________

b. Is the process in control?

Yes

7.
value:
6.00 points

After a number of complaints about its directory assistance, a telephone company examined samples of calls to determine the frequency of wrong numbers given to callers. Each sample consisted of 112 calls.

SAMPLE
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Number of errors 4 3 5 3 2 6 4 3 5 10 3 3 5 3 6 2
________________________________________

a. Determine 95 percent limits. (Do not round your intermediate calculations. Round your final answers to 3 decimal places.)
UCL LCL ________________________________________

b. Is the process stable (i.e., in control)?

Yes

8.
value:
6.00 points

Specifications for the computer upgrades are 77 minutes and 81 minutes. Estimate the percentage of process output that can be expected to fall within the specifications. (Round your answer to 1 decimal place. Omit the “%” sign in your response.)

SAMPLE
1 2 3 4 5 6
79.2 82.8 79.6 78.9 81.7 79.7
81.9 78.7 79.6 84.2 79.6 80.6
80.0 81.0 78.9 79.7 80.4 79.1
78.4 80.4 80.3 79.4 78.5 80.0
81.0 80.1 80.8 80.6 78.8 81.1
________________________________________

Expected process output % 9.
value:
6.00 points

A process that produces computer chips has a mean of .04 defective chip and a standard deviation of .003 chip. The allowable variation is from .037 to .043 defective.

a. Compute the capability index (Cp) for the process. (Round your intermediate calculations to 3 decimal places and final answer to 2 decimal places.)

Capability index
b. Is the process capable?

Yes

10.
value:
6.00 points

Suppose your manager presents you with the following information about machines that could be used for a job, and wants your recommendation on which one to choose. The specification width is .48 mm. In this instance, you can narrow the set of choices, but you probably wouldn’t make a recommendation without an additional piece of information. (Round your answers to 3 decimal places.)

Machine Cost per
Unit ($) Standard Deviation (mm)
A 18 .055
B 12 .060
C 12 .075
D 10 .064
________________________________________

Process Cp
A B C D ________________________________________

We can narrow the choices to processes . 11.
value:
6.00 points

Each of the processes listed is noncentered with respect to the specifications for that process.

Process Mean Standard
Deviation Lower
Spec Upper
Spec
H 19.2 .42 18.1 20.6
K 26.9 1.06 24.0 30.4
T 22.1 .67 20.4 24.2
________________________________________

Compute the appropriate capability index for each, and decide if the process is capable. (Round your answers to 2 decimal places.)

Process Cpk Capable?
H
K
T
________________________________________
12.
value:
6.00 points

An appliance manufacturer wants to contract with a repair shop to handle authorized repairs in Indianapolis. The company has set an acceptable range of repair time of 50 minutes to 91.6 minutes. Two firms have submitted bids for the work. In test trials, one firm had a mean repair time of 74 minutes with a standard deviation of 4.0 minutes and the other firm had a mean repair time of 72 minutes with a standard deviation of 5.1 minutes. Which firm would you choose? (Do not round intermediate calculations. Round your answers to 2 decimal places.)

Firm Cpk
1 2 ________________________________________

Thus, the firm is capable.
Portfolio 3 Part 3 (chapter 11)
1.
value:
5.00 points

Planners for a company that makes several models of skateboards are about to prepare the aggregate plan that will cover six periods. They have assembled the following information:

Period 1 2 3 4 5 6 Total
Forecast 200 200 300 400 500 200 1,800
________________________________________

Costs
Output
Regular time = $ 2 per skateboard
Overtime = $ 3 per skateboard
Subcontract = $ 6 per skateboard
Inventory = $ 2 per skateboard per period on average inventory
Back orders = $ 3 per skateboard per period
________________________________________

They now want to evaluate a plan that calls for a steady rate of regular-time output, mainly using inventory to absorb the uneven demand but allowing some backlog. Overtime and subcontracting are not used because they want steady output. They intend to start with zero inventory on hand in the first period. Assume a level output rate of 300 units (skateboards) per period with regular time (i.e., 1,800/6 = 300). Note that the planned ending inventory is zero. There are 15 workers, and each can produce 20 skateboards per period.

The president of the firm has decided to shut down the plant for vacation and installation of new equipment in period 4. After installation, the cost per unit will remain the same, but the output rate for regular time will be 450. Regular output is the same for periods 1, 2, and 3; 0 for period 4; and 450 for each of the remaining periods. Note, though, that the forecast of 400 units in period 4 must be dealt with.

Prepare the aggregate plan, and compute its total cost. (Negative amounts should be indicated by a minus sign. Leave no cells blank – be certain to enter “0” wherever required. Omit the “$” sign in your response.)

Period 1 2 3 4 5 6 Total
Forecast 200 200 300 400 500 200 1,800
Output
Regular

Overtime
Subcontract
Output-
Forecast

Inventory
Beginning

Ending

Average

Backlog

$ Overtime
Subcontract
Inventory

Backorder

$ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________
________________________________________
2.
value:
5.00 points

Planners for a company that makes several models of skateboards are about to prepare the aggregate plan that will cover six periods. They have assembled the following information:

Period 1 2 3 4 5 6 Total
Forecast 200 200 300 400 500 200 1,800
________________________________________

Costs
Output
Regular time = $ 7 per skateboard
Overtime = $ 4 per skateboard
Subcontract = $ 5 per skateboard
Inventory = $ 1 per skateboard per period on average inventory
Back orders = $ 8 per skateboard per period
________________________________________

Suppose that the regular output rate will drop to 290 units per period due to an expected change in production requirements. Costs will not change. Prepare an aggregate plan and compute its total cost for each of these alternatives:

a. Use overtime at a fixed rate of 20 units per period as needed. Plan for an ending inventory of zero for period 6. Backlogs cannot exceed 90 units per period. (Negative amounts should be indicated by a minus sign. Leave no cells blank – be certain to enter “0” wherever required. Omit the “$” sign in your response.)

Period 1 2 3 4 5 6 Total
Forecast 200 200 300 400 500 200 1,800
Output
Regular

Overtime

Output-
Forecast

Inventory
Beginning

Ending

Average

Backlog

$ Overtime

Inventory

Backorder

________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________
________________________________________

b-1. Use subcontracting at a maximum rate of 50 units per period; the usage need not be the same in every period. Have an ending inventory of zero in the last period. Again backlogs cannot exceed 90 units in any period. (Negative amounts should be indicated by a minus sign. Leave no cells blank – be certain to enter “0” wherever required. Omit the “$” sign in your response.)

Period 1 2 3 4 5 6 Total
Forecast 200 200 300 400 500 200 1,800
Output
Regular

Subcontract

Output-
Forecast

Inventory
Beginning

Ending

Average

Backlog

$ Subcontract

Inventory

Backorder

b-2. Compare these two plans. Which plan is better?

Second

First

Neither

3.
value:
5.00 points

Nowjuice, Inc., produces Shakewell® fruit juice. A planner has developed an aggregate forecast for demand (in cases) for the next six months.

Month May Jun Jul Aug Sep Oct
Forecast 4,000 4,800 5,600 7,200 6,400 5,000
________________________________________

Use the following information to develop aggregate plans.
Regular production cost $ 12 per case
Regular production capacity 5,000 cases
Overtime production cost $ 18 per case
Subcontracting cost $ 34 per case
Holding cost $ 3 per case per month
Beginning inventory 0
________________________________________

1. Develop an aggregate plan using each of the following guidelines and compute the total cost for each plan.

a. Use level production. Supplement using overtime as needed. (Negative amounts should be indicated by a minus sign. Leave no cells blank – be certain to enter “0” wherever required. Omit the “$” sign in your response.)

Period May Jun Jul Aug Sep Oct Total
Forecast 4,000 4,800 5,600 7,200 6,400 5,000 33,000
Output
Regular

Overtime

Output – Forecast

Inventory
Beginning

Ending

Average

Backlog

$ Overtime

Inventory

Back orders

b. Use a combination of overtime (500 cases per period maximum), inventory, and subcontracting (500 cases per period maximum) to handle variations in demand. (Negative amounts should be indicated by a minus sign. Leave no cells blank – be certain to enter “0” wherever required. Omit the “$” sign in your response.)

Period May Jun Jul Aug Sep Oct Total
Forecast 4,000 4,800 5,600 7,200 6,400 5,000 33,000
Output
Regular

Overtime

Subcontract

Output – Forecast

Inventory
Beginning

Ending

Average

Backlog

$ Overtime

Subcontract

Inventory

Back orders

c. Use overtime up to 750 cases per period and inventory to handle variations in demand. (Negative amounts should be indicated by a minus sign. Leave no cells blank – be certain to enter “0” wherever required. Omit the “$” sign in your response.)

Period May Jun Jul Aug Sep Oct Total
Forecast 4,000 4,800 5.600 7,200 6,400 5,000 33,000
Output
Regular

Overtime

Output – Forecast

Inventory
Beginning

Ending

Average

Backlog

$ Overtime

Hire/Lay off

Inventory

Back orders

2. Which plan has the lowest total cost?

Third

First

Neither

Second

4.
value:
5.00 points

Given the following information set up the problem in a transportation table and solve for the minimum-cost plan:

PERIOD
1 2 3
Demand 550 700 750
Capacity
Regular 500 500 500
Overtime 50 50 50
Subcontract 120 120 100
Beginning inventory 100
Costs
Regular time $ 58 per unit
Overtime $ 86 per unit
Subcontract $ 93 per unit
Inventory carrying cost $ 2 per unit per month
Back-order cost $ 3 per unit per month
________________________________________

Suppose that an increase in warehousing costs and other costs brings inventory carrying costs to $2 per unit per month. All other costs and quantities remain the same. Determine a revised solution to this transportation problem. (Omit the “$” sign in your response.)

Optimal total cost $ 5.
value:
5.00 points

Prepare a master production schedule for industrial pumps in the manner of the following table. Use the MPS rule to “schedule production when the projected on-hand inventory would be less than 10 without production.” Suppose that a production lot size of 70 pumps is used. (Leave no cells blank – be certain to enter “0” wherever required.)

June July
Initial Inventory = 60 1 2 3 4 5 6 7 8
Forecast 30 30 30 30 40 40 40 40
Customer orders (committed) 33 20 10 4 2
Projected on-hand inventory

MPS

ATP

________________________________________
6.
value:
5.00 points

Prepare a master schedule given this information: It is now the end of week 1; customer orders are 25 for week 2, 16 for week 3, 11 for week 4, 8 for week 5, and 3 for week 6. Use the MPS rule of ordering production when projected on-hand inventory would be negative without production. Suppose that a production lot size of 70 pumps is used. (Leave no cells blank – be certain to enter “0” wherever required.)

June July
60 1 2 3 4 5 6 7 8
Forecast 30 30 30 30 40 40 40 40
Customer orders (committed) 31 25 16 11 8 3
Projected on-hand inventory

MPS

ATP

________________________________________

Portfolio 3 Part 4 (chapter 12)

1.
value:
3.00 points

Given the following diagram for a product, determine the quantity of each component required to assemble one unit of the finished product.
Item Quantity
E F G H J D L A ________________________________________
2.
value:
3.00 points

The following table lists the components needed to assemble an end item, lead times, and quantities on hand.
Item End B C D E F G H
LT (wk) 1 2 3 3 1 2 1 2
Amount on hand 0 10 10 25 12 30 5 0
________________________________________

a. If 23 units of the end item are to be assembled, how many additional units of E are needed? (Hint: You don’t need to develop an MRP plan to determine this.)

Additional units
b. An order for the end item is scheduled to be shipped at the start of week 15. What is the latest week that the order can be started and still be ready to ship on time? (Hint: You don’t need to develop an MRP plan for this part either.)

The latest week
3.
value:
3.00 points

The following table lists the components needed to assemble an end item, lead times (in weeks), and quantities on hand.

Item Lead Time Amount
on Hand Direct Components
End 1 – L(2), C(1), K(3)
L 2 10 B(2), J(3)
C 3 15 G(2), B(2)
K 3 20 H(4), B(2)
B 2 30
J 3 30
G 3 5
H 2 –
________________________________________

a. If 45 units of the end item are to be assembled, how many additional units of B are needed? (Hint: You don’t need to develop an MRP plan.)

Additional units
b. An order for the end item is scheduled to be shipped at the start of week 9. What is the latest week that the order can be started and still be ready to ship on time? (Hint: You don’t need to develop an MRP plan.)

The latest week 4.
value:
6.00 points

A table is assembled using three components, as shown in the accompanying product structure tree. The company that makes the table wants to ship 97 units at the beginning of day 4, 144 units at the beginning of day 5, and 194 units at the beginning of day 7. Receipts of 100 wood sections are scheduled at the beginning of day 2. There are 160 legs on hand. An additional 10 percent of the order size on legs is added for safety stock. There are 60 braces on hand with no safety stock requirement for braces. Lead times (in days) for all items are shown in the following table. Prepare a material requirements plan using lot-for-lot ordering. (Incorporate the safety stock for the legs by using the following formula: Planned order-receipts = Net Requirements * (1 + Safety Stock %). Round up any fractional values. Then carry the safety stock forward in subsequent on-hand inventory calculations. Leave no cells blank – be certain to enter “0” wherever required.)

Quantity Lead Time
1 – 200 1
201 – 550 2
551 – 999 3
________________________________________
Master Schedule

Day Beg. Inv. 1 2 3 4 5 6 7
Quantity

________________________________________

Table Beg. Inv. 1 2 3 4 5 6 7
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned-order receipts

Planned-order releases

________________________________________

Wood Sections Beg. Inv. 1 2 3 4 5 6 7
Gross requirements

Scheduled receipts

Projected on hand

Net requirements

Planned-order receipts

Planned-order releases

________________________________________

Braces Beg. Inv. 1 2 3 4 5 6 7
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned-order receipts

Planned-order releases

________________________________________

Legs Beg. Inv. 1 2 3 4 5 6 7
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned-order receipts

Planned-order releases

5.
value:
3.00 points

76 units of end item X are needed at the beginning of week 6, and another 30 units are needed at the beginning of week 8.

Prepare a material requirements plan for component D. D can only be ordered in whole cases (50 units per case). One case of D is automatically received every other week, beginning in week 1 (i.e., weeks 1, 3, 5, 7). Also, there are 30 units of B and 20 units of D now on hand. Lead times for all items are a function of quantity: one week for up to 100 units, two weeks for 101 to 200 units, three weeks for 201 to 300 units, and four weeks for 301 or more units. (Leave no cells blank – be certain to enter “0” wherever required.)

Part D Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts

On hand

Net requirements

Planned-order receipt

Planned-order release

________________________________________
6.
value:
3.00 points

Oh No!, Inc., sells three models of radar detector units. It buys the three basic models (E, F, and G) from a Japanese manufacturer and adds one, two, or four lights (component D) to further differentiate the models. D is bought from a domestic producer.

Lead times are one week for all items except C, which is two weeks. There are ample supplies of the basic units (E, F, and G) on hand. There are also 10 units of B, 10 units of C, and 25 units of D on hand. Lot-sizing rules are lot-for-lot ordering for all items except D, which must be ordered in multiples of 100 units. There is a scheduled receipt of 100 units of D in week 1.

The master schedule calls for 44 units of A to be produced at the beginning of week 4, 57 units of B at the beginning of week 5, and 30 units of C at the beginning of week 6.

Prepare a material requirements plan for D and its parents. (Leave no cells blank – be certain to enter “0” wherever required.)

Parent A:

LT = 1 wk. Beg. Inv. 1 2 3 4 5 6
Gross requirements

Scheduled receipts

Projected on hand

Net requirements

Planned order receipt

Planned order release

________________________________________

Parent B:

LT = 1 wk. Beg. Inv. 1 2 3 4 5 6
Gross requirements

Scheduled receipts

Projected on hand

Net requirements

Planned order receipt

Planned-order release

________________________________________

Parent C:

LT = 2 wks. Beg. Inv. 1 2 3 4 5 6
Gross requirements

Scheduled receipts

Projected on hand

Net requirements

Planned order receipt

Planned-order release

________________________________________

Plan D:

LT = 1 wk. Beg. Inv. 1 2 3 4 5 6
Gross requirements

Scheduled receipts

Projected on hand

Net requirements

Planned-order receipt

Planned order release

________________________________________

7.
value:
3.00 points

Assume that you are the manager of a shop that assembles power tools. You have just received an order for 59 chain saws, which are to be shipped at the start of week 8. Pertinent information on the saws is

Item Lead Time (weeks) On Hand Components
Saw 2 15 A(2), B(1), C(4)
A 1 10 E(3), D(1)
B 2 5 D(2), F(3)
C 2 65 E(2), D(2)
D 1 20
E 1 10
F 2 30
________________________________________

b. Develop the material requirements plan for component E using lot-for-lot ordering. (Leave no cells blank – be certain to enter “0” wherever required.)

Item: E(3) & E(2) LT = 1 wk. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned order receipt

Planned order release

8.
value:
6.00 points

A firm that produces electric golf carts has just received an order for 163 carts, which must be ready for delivery at the start of week 8. Information concerning the product structure, lead times, and quantities on hand is shown in the following table. Use this information to do each of the following:

Parts List for Electric Golf Cart Lead Time Quantity on Hand
Electric golf cart 1 0
Top 1 40
Base 1 20
Top
Supports (4) 1 200
Cover 1 0
Base
Motor 2 300
Body 3 50
Seats (2) 2 120
Body
Frame 1 35
Controls 1 0
Wheel assemblies (4) 1 240
________________________________________

Develop a material requirements plan that will provide 163 golf carts by week 8 assuming lot-for-lot ordering.(Negative amounts should be indicated by a minus sign. Leave no cells blank – be certain to enter “0” wherever required.)

Master Schedule for golf carts

Week Beg. Inv. 1 2 3 4 5 6 7 8
Quantity

________________________________________

Item: Golf Cart LT = 1 wk. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand
Net requirements

Planned order receipts

Planned order releases

________________________________________

Item: Top LT = 1 wk. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned order receipts

Planned order releases

________________________________________

Item: Supports (4) LT = 1 wk. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned order receipts

Planned order releases

________________________________________

Item: Cover LT = 1 wk. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand
Net requirements

Planned order receipts

Planned order releases

________________________________________

Item: Base LT = 1 wk. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned order receipts

Planned order releases

________________________________________

Item: Motor LT = 2 wks. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned order receipts
Planned order releases
________________________________________

Item: Body LT = 3 wks. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned order receipts

Planned order releases

________________________________________

Item: Seats LT = 2 wks. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned order receipts

Planned order releases

________________________________________

Item: Frame LT = 1 wk. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned order receipts

Planned order releases

________________________________________

Item: Controls LT = 1 wk. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand
Net requirements

Planned order receipts

Planned order releases

________________________________________

Item: Wheel Assemblies LT = 1 wk. Beg. Inv. 1 2 3 4 5 6 7 8
Gross requirements

Scheduled receipts
Projected on hand

Net requirements

Planned order receipts

Planned order releases

OPERATIONS MANAGEMENT, with equations

labor productivity

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