The Fastgro Fertilizer Company distributes fertilizer to various lawn and garden shops. The company must base its quarterly production schedule on a forecast of how many tons of fertilizer will be demanded from it. The company has gathered the following data for the past 3 years from its sales records:
a. Compute a three-quarter moving average forecast for quarters 4 through 13, and compute the forecast error for each quarter.
b. Compute a five-quarter moving average forecast for quarters 6 through 13, and compute the forecast error for each quarter.
c. Compute a weighted three-quarter moving average forecast, using weights of .50, .33, and.17 for the most recent, next most recent, and most distant data, respectively, and compute the forecast error for each quarter.
d. Compare the forecasts developed in (a), (b), and (c), using cumulative error. Which forecast appears to be most accurate? Do any of them exhibit any bias?
e. Graph the demand data. Can you identify any trends, cycles, or seasonal patterns?
> The Pacific Lumber Company and Mill processes 10,000 logs annually, operating 250 days per year. Immediately upon receiving an order, the logging company’s supplier begins delivery to the lumber mill, at a rate of 60 logs per day. The lumber mill has det
> Craftwood Furniture Company is a U.S.-based furniture manufacturer that offshored all of its actual manufacturing operations to China about a decade ago. It set up a distribution center in Hong Kong, from which the company ships its items to the United S
> In Problem 32 in Chapter 15, the supplier receives shipments of partially completed laptops from its manufacturing facility in Southeast Asia, which has maximum production rate of 200 units per day. Using the forecast of annual demand developed in that p
> Tara, an apparel store, has forecasted a sale of 100,000 meters of dress material for the next year. Its spinning mill can produce 500 meters of materials per day. The cost of setup per production run is C6,000. The store needs to use special materials t
> The Honda dealership at your city forecasted that it could sell around 500 cars in the next year. The annual carrying cost of a car is ¥500,000, and the ordering cost which involves order processing and transportation is ¥300,000. Once an order is made,
> The purchasing manager for the Atlantic Steel Company must determine a policy for ordering coal to operate 12 converters. Each converter requires exactly 5 tons of coal per day to operate, and the firm operates 360 days per year. The purchasing manager h
> A farm owner is going to erect a maintenance building with a connecting electrical generator and water tank. The activities, activity descriptions, and estimated durations are given in the following table: (Notice that the activities are defined not by n
> A furniture store produces tables and doors and sells them through its outlets across the country. The wood working machines are first set for producing tables and the produced tables are stocked for meeting the customers’ demand. Once enough tables are
> The Wood Valley Dairy makes cheese to supply to stores in its area. The dairy can make 250 pounds of cheese per day (365 days per year), and the demand at area stores is 180 pounds per day. Each time the dairy makes cheese, it costs $125 to set up the pr
> Hayes Electronics stocks and sells a particular brand of personal computer. It costs the firm $450 each time it places an order with the manufacturer for the personal computers. The cost of carrying one PC in inventory for a year is $170. The store manag
> Eurotronics manufactures components for use in small electronic products such as computers, CD players, and radios at plants in Belgium, Germany, and France. The parts are transported by truck to Hamburg, where they are shipped overseas to customers in M
> Emily Andrews has invested in a science and technology mutual fund. Now she is considering liquidating and investing in another fund. She would like to forecast the price of the science and technology fund for the next month before making a decision. She
> The Bayside Fountain Hotel is adjacent to County Coliseum, a 24,000-seat arena that is home to the city’s professional basketball and ice hockey teams and that hosts a variety of concerts, trade shows, and conventions throughout the yea
> The Victory Plus Mutual Fund of growth stocks has had the following average monthly price for the past 10 months: Compute the exponentially smoothed forecast with a = .40, the adjusted exponential smoothing fore- cast with a = .40 and b = .30 and the lin
> The dean of the college of business at Tech has initiated a fund-raising campaign. One of the selling points he plans to use with potential donors is that increasing the college’s private endowment will improve its ranking among all bus
> The manager of the Bayville police department motor pool wants to develop a forecast model for annual maintenance on police cars, based on mileage in the past year and age of the cars. The following data have been collected for eight different cars: a. U
> In Problem 42, Infoworks believes its printer sales are also related to the average price of its printers. It has collected historical data on average printer prices for the past 10 years, as follows: a. Using Excel, develop the multiple regression equat
> Construct a Gantt chart for the following set of activities, and indicate the project completion time:
> Tech administrators believe their freshman applications are influenced by two variables: tuition and the size of the applicant pool of eligible high school seniors in the state. The following data for an 8-year period show the tuition rates (per semester
> The State of Virginia has instituted a series of standards of learning (SOL) tests in math, history, English, and science that all high school students must pass with a grade of 70 before they are allowed to graduate and receive their diplomas. The schoo
> The admission data for freshmen at Tech during the past 10 years are as follows: Tech’s admission objective is a class of 5,000 entering freshmen, and Tech wants to forecast the percentage of offers it will likely have to make to achiev
> The Port of Savannah is considering an expansion of its container terminal. The port has experienced the following container throughput during the past 12 years, expressed as TEUs (i.e., 20-foot equivalent units, a standard unit of measure for containers
> The Valley United Soccer Club has boys’ and girls’ travel soccer teams at all age levels up to 18 years. The club has been successful and grown in popularity over the years; however, an obstacle to its continued growth
> The Wellton Fund is a balanced mutual fund that includes a mix of stocks and bonds. Following are the year-end share prices of the fund and Dow Jones Industrial Average (DJIA) for a 20-year period: Develop a linear regression model for these data and for
> A cooking oil distributor distributes oil to major supermarkets in the region. Though a person’s daily consumption of oil seems to be almost the same, the distributor’s demand for oil fluctuates every month. The distri
> In Problem 48, one of the new products in the GreenClean line that Klorax is ready to introduce is an all-purpose cleaner, and Klorax is attempting to forecast what demand might be like 5 years into the future. However, it has no historical demand data t
> To take advantage of the burgeoning public interest in sustainability, Klorax has developed a non- synthetic line of natural cleaning products called GreenClean. One of the first sustainable products Klorax introduced was a natural cold-water detergent.
> The busiest time of the day at the Taco Town fast-food restaurant is between 11:00 A.M. and 2:00 p.M. Taco Town’s service is very labor dependent, and a critical factor for providing quick service is the number of employees on hand duri
> Liu and Fong is a global supplier of denim jeans for apparel companies around the world. Its supply chain includes cotton production in the United States, fabric manufacturing in Southeast Asia and the Pacific Rim; jeans manufacturing in the Far and Midd
> The consumer loan department at Central Union Bank and Trust wants to develop a forecasting model to help determine its potential loan application volume for the coming year. Because adjust- able-rate home mortgages are based on government long-term Trea
> Develop an adjusted exponential smoothing forecast model (a = .40 and b = .40) for the data in Problem 44 to forecast seat occupancy and compare its accuracy with the seasonally adjusted model developed in (a).
> Arrow Air is a regional East Coast airline that has collected data for the percentage of avail- able seats occupied on its flights for four quarters—(1) January–March, (2) April–June, (3) Julyâ&
> Develop an exponential smoothing model with a = .30 for the data in Problem 42 to forecast printer demand in year 11 and compare its accuracy to the linear trend line forecast developed in (a).
> Infoworks is a large computer discount store that sells computers and ancillary equipment and software in the town where State University is located. Infoworks has collected historical data on computer sales and printer sales for the past 10 years, as fo
> The Gametime Hat Company manufactures baseball caps that have various team logos in an assortment of designs and colors. The company has had monthly sales for the past 24 months as follows: Develop a forecast model using the method you believe best, and
> Apperson and Fitz is a chain of clothing stores that caters to high school and college students. It publishes a quarterly catalog and operates a Web site that features provocatively attired males and females. The Web site is very expensive to maintain, a
> The chairperson of the department of management at State University wants to forecast the number of students who will enroll in production and operations management (POM) next semester to determine how many sections to schedule. The chair has accumulated
> Employees at Precision Engine Parts Company produce parts according to exact design specifications. The employees are paid according to a piece-rate system, wherein the faster they work and the more parts they produce, the greater their chances for month
> Some members of management of the Fairface Cosmetics Firm believe that demand for its products is related to the promotional activities of local department stores where the cosmetics are sold. However, others in management believe that other factors, suc
> In Problem 36 in Chapter 6, KanTech Corporation ships electronic components in containers from seaports in Europe to U.S. ports, from which the containers are transported by truck or rail to inland ports and then transferred to an alternative mode of tra
> PAWV Power and Light has contracted with a –waste- disposal firm to have nuclear waste from its nuclear power plants in Pennsylvania disposed of at a—government—operated nuclear waste disposal site in
> Explain the numerical value of the slope of the linear regression equation in Problem 33.
> Develop a linear trend line model for the freshman applications data at State University in Problem 35. a. Does this forecast appear to be more or less accurate than the linear regression forecast developed in Problem 35? Justify your answer. b. Compute
> Administrators at State University believe that decreases in the number of freshman applications that they have experienced are directly related to tuition increases. They have collected the following enrollment and tuition data for the past decade: a.
> Compute the coefficient of determination for the data in Problem 33, and explain its meaning.
> The manager of Gilley’s Ice Cream Parlor needs an accurate forecast of the demand for ice cream. The store orders ice cream from a distributor a week ahead; if the store orders too little, it loses business, and if it orders too much, t
> Bell Inc. is a computer company that gets most of its component parts from suppliers in Southeast Asia, who ship to small warehouses called “revolvers” (for revolving inventory) near Bell’s main assem
> The DirectCast cable TV company is a national chain that services the small college town that is home to Tech, with a student population of almost 30,000. The company has generally been able to handle service calls and installations in the past, but a gr
> The Tech power plant burns coal and natural gas to generate steam and electricity for all campus buildings. The annual coal consumption at the plant has increased annually for the past 8 years due to an aggressive campus building program. The following t
> Suntrek is a global manufacturer and supplier of denim jeans to apparel retailers around the world. It purchases baled cotton around the world, ships it to its denim fabric factories, then to its denim jeans manufacturing facilities. Its cotton purchases
> A water station (1) is planned to supply a new city (13) with water through the current network of pipes and substations. The diagram below shows the water flow capacity of the different pipes of the current network in 1000 gallons per minute. Use Excel
> Bernice’s Pizza Restaurant opened the previous year, and in addition to sit-down restaurant service they filled take-out orders (picked up by customers) and some delivery orders using the owner’s car. The owner, Bernic
> A group of business students at Tech organized a student club called Prism to develop and disseminate content about business majors through a Web site they created and social media sites. Prism would like for the academic departments to use its Web site
> Carpet City wants to develop a means to forecast its carpet sales. The store manager believes that the store’s sales are directly related to the number of new housing starts in town. The manager has gathered data from county records on
> The manager of the Ramona Inn Hotel near Cloverleaf Stadium believes that how well the local Blue Sox professional baseball team is playing has an impact on the occupancy rate at the hotel during the summer months. Following are the number of victories f
> The Jersey Dairy Products Company produces cheese, which it sells to supermarkets and food- processing companies. Because of concerns about cholesterol and fat in cheese, the company has seen demand for its products decline during the past decade. It is
> Develop an exponential smoothing forecast with a = .20 for the demand data in Problem 1. Compare this forecast with the 3-month moving average computed in part (a) of Problem 1, using MAD, and indicate which forecast seems to be more accurate.
> RAP Computers assembles personal computers from generic parts it purchases at a discount, and it sells the units by phone orders it receives from customers responding to the company’s ads in trade journals. The business has developed an
> Aztec Industries has developed a forecasting model that was used to forecast during a 10-month period. The forecasts and actual demand were as follows: Measure the accuracy of the forecast by using MAD, MAPD, and cumulative error. Does the forecast metho
> The emergency room at the new Community Hospital selected every other week during the past 5 months to observe the number of patients during two parts of each week—the weekend (Friday through Sunday) and weekdays (Monday through Thursda
> The McDonald’s store at a busy mall has collected its last 10 months’ sales (in thousands of meal) data for its fast selling a la carte meal—The Feast McChicken. To provide consistent taste in chicken
> A manufacturing company produces different variations of a product at different work centers in its plant on a daily basis. Following is a network showing the various work centers in the plant, the daily capacities at each work center, and the flow of th
> LT manufactures smartphone components, which are dependent on the global demand for smart- phones. Following are the yearly global sales (in million units) for the past 8 years. Develop a linear trend line model to forecast smartphone sales for years 9,
> Dubai-fly airline operates flights from Dubai to Milan. The demand for airline seats varies from month to month. There are few peak seasonal demands, for instance, just before and after Christmas and during August and September when schools reopen after
> Metro Food Vending operates vending machines in office buildings, the airport, bus stations, colleges, and other businesses and agencies around town, and it operates vending trucks for building and construction sites. The company believes its sandwich sa
> The Northwoods Outdoor Company is a catalog sales operation that specializes in outdoor recreational clothing. Demand for its items is very seasonal, peaking during the Christmas season and during the spring. It has accumulated the following data for ord
> The Beaver Creek Pottery Company sells bowls and mugs, hand-made by Native American artisans, at a craft store and through a Web site. Making these items requires a special type of clay and a large amount of individual person-hours, so for planning purpo
> The River is a literary magazine published by the English Department at Tech. It has a 70-year history and enjoys an excellent reputation for providing a literary outlet for aspiring Appalachian writers in particular. However, its sales, mostly through i
> The Cat Creek Mining Company mines and ships coal. It has experienced the following demand for coal during the past 8 years: Develop an adjusted exponential smoothing model (a = .30, b = .20) and a linear trend line model and compare the forecast accurac
> Monaghan’s Pizza delivery service has randomly selected 8 weekdays during the past month and recorded orders for pizza at four different time periods per day: Develop a seasonally adjusted forecasting model for daily pizza demand and fo
> Develop a seasonally adjusted forecast for the demand data for fertilizer found in Problem 3. Then use a linear trend line model to compute a forecast estimate for demand in year 4.
> The Whistle Stop Cafe in Weems, Georgia, is well known for its popular homemade ice cream, made in a small plant in back of the cafe. People drive all the way from Atlanta and Macon to buy the ice cream. The two women who own the cafe want to develop a f
> Given the following network, with the indicated flow capacities along each branch, determine the maximum flow from source node 1 to destination node 10 and the flow along each path:
> A banana growers’ society grows banana in a region. After planting saplings, it takes around 10 months to harvest stalks of bananas. Since the production cycle is long and strong wind affects the plantation, it becomes impossible to inc
> The time between arrivals of oil tankers at a loading dock at Prudhoe Bay is given by the following probability distribution: The time required to fill a tanker with oil and prepare it for sea is given by the following probability distribution: a. Simula
> First American Bank is trying to determine whether it should install one or two drive-through teller windows. The following probability distributions for arrival intervals and service times have been developed from historical data: Assume that in the two
> Sound Warehouse in Georgetown sells CD players (with speakers), which it orders from Fuji Electronics in Japan. Because of shipping and handling costs, each order must be for five CD players. Because of the time it takes to receive an order, the warehou
> Every time a machine breaks down at the Dynaco Manufacturing Company (Problem 3), 1, 2, or 3 hours are required to fix it, according to the following probability distribution: a. Simulate the repair time for 20 weeks, and then compute the average weekly
> Simulate the decision situation described in Problem 18(a) at the end of Chapter 12 for 20 weeks, and recommend the best decision.
> Solve Problem 21 at the end of Chapter 12 by using simulation.
> In Chapter 8, Figure 8.6 shows a simplified project network for building a house, as follows: There are four paths through this network: The time parameters (in weeks) defining a triangular probability distribution for each activity are provided as follo
> The Management Science Association (MSA) has arranged to hold its annual conference at the Riverside Hotel in Orlando next year. Based on historical data, the MSA believes the number of rooms it will need for its members attending the conference is norma
> In Chapter 16, the formula for the optimal order quantity of an item, Q, given its demand, D, ordering cost, Co, and the cost of holding, or carrying, an item in inventory, Cc, is as follows: The total inventory cost formula is Ordering cost, Co, and car
> Suppose in Problem 35 that the processing cost per unit at each plant is different because of different machinery, workers’ abilities, overhead, and so on, according to the following table: There are no differentiated costs at stage 5,
> Erin Jones has $100,000 and, to diversify, she wants to invest equal amounts of $50,000 each in two mutual funds selected from a list of four possible mutual funds. She wants to invest for a 3-year period. She has used historical data from the four funds
> In Problem 23, assume that production capacity at Burlingham Mills for the Troy Clothing Company contract is normally distributed, with a mean of 320 yards per month and a standard deviation of 120 yards, and that Troy Clothing’s demand is uniformly dist
> In Problem 21, assume that the students at Randolph College have redefined the probability distributions of their dates at Salem College as follows: Physical attractiveness is uniformly distributed from 1 to 5; intelligence is defined by a triangular dis
> In Problem 20, assume that the sales volume for Western Outfitters Store is normally distributed, with a mean of 600 pairs of jeans and a standard deviation of 200; the price is uniformly distributed, with a minimum of $22 and a maximum of $28; and the v
> The Dynaco Manufacturing Company produces a product in a process consisting of operations of five machines. The probability distribution of the number of machines that will break down in a week follows: a. Simulate the machine breakdowns per week for 20
> Tracy McCoy is shopping for a new car. She has identified a particular sports utility vehicle she likes but has heard that it has high maintenance costs. Tracy has decided to develop a simulation model to help her estimate maintenance costs for the life
> For the Bigelow Manufacturing example in this chapter, re-create the simulation for the improved maintenance program shown in Table 14.11 and Exhibit 14.8 using Crystal Ball. For the improved program assume that the repair time is normally distributed wi
> For the Bigelow Manufacturing example in this chapter, re-create the simulation shown in Table 14.10 and Exhibit 14.7 using Crystal Ball. Assume that the repair time is normally distributed with a mean of 2.15 days and a standard deviation of 0.8 day. As
> Perform the Crystal Ball simulation in Problem 25, assuming that demand is normally distributed with a mean of 2.5 and a standard deviation of 1.2 laptops.
> For the ComputerWorld example in this chapter, recreate the simulation shown in Exhibit 14.2 using Crystal Ball. Assume that demand is normally distributed with a mean of 1.5 laptops and a standard deviation of 0.8. Using Crystal Ball determine average w
> Diamant Foods Company produces a variety of food prod- ucts, including a line of candies. One of its most popular candy items is Divine Diamonds, a bag of a dozen individually wrapped diamond-shaped candies made primarily from a blend of dark and milk ch
> A baseball game consists of plays that can be described as follows: Distributions for these plays for two teams, the White Sox (visitors) and the Yankees (home), are as follows: Simulate a nine-inning baseball game using the preceding information.2 Sourc
> Burlingham Mills produces denim cloth that it sells to jeans manufacturers. It is negotiating a contract with Troy Clothing Company to provide denim cloth on a weekly basis. Burlingham has established its monthly available production capacity for this co
> In Problem 21, discuss how you might assess the accuracy of the average rating for Salem College students based on only 20 simulated dates.
> Randolph College and Salem College are within 20 miles of each other, and the students at each college frequently date each other. The students at Randolph College are debating how good their dates are at Salem College. The Randolph students have sampled
> The Western Outfitters Store specializes in denim jeans. The variable cost of the jeans varies according to several factors, including the cost of the jeans from the distributor, labor costs, handling, packaging, and so on. Price also is a random variabl