Solutions Statistics for Business and Economics 10 Ed. Anderson. Chapter 21

21.1 The following payoff table shows profit for a decision analysis problem with two decision alternatives and three states of nature....
a. Construct a decision tree for this problem.
b. Suppose that the decision maker obtains the probabilities P(s1) = .65, P(s2) = .15, and P(s3) = .20. Use the expected value approach to determine the optimal decision.

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21.2 A decision maker faced with four decision alternatives and four states of nature develops the following profit payoff table....The decision maker obtains information that enables the following probabilities assessments: P(s1) = .5, P(s2) = .2, P(s3) = .2, and P(s1) = .1.
a. Use the expected value approach to determine the optimal decision.
b. Now assume that the entries in the payoff table are costs. Use the expected value approach to determine the optimal decision.

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21.3 Hudson Corporation is considering three options for managing its data processing operation:continue with its own staff, hire an outside vendor to do the managing (referred to as outsourcing), or use a combination of its own staff and an outside vendor. The cost of the operation depends on future demand. The annual cost of each option (in thousands of dollars) depends on demand as follows....
a. If the demand probabilities are .2, .5, and .3, which decision alternative will minimize the expected cost of the data processing operation? What is the expected annual cost associated with your recommendation?
b. What is the expected value of perfect information?

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21.4 Myrtle Air Express decided to offer direct service from Cleveland to Myrtle Beach. Management must decide between a full price service using the company’s new fleet of jet aircraft and a discount service using smaller capacity commuter planes. It is clear that the bestchoice depends on the market reaction to the service Myrtle Air offers. Management developed estimates of the contribution to profit for each type of service based upon two possible levels of demand for service to Myrtle Beach: strong and weak. The following table shows the estimated quarterly profits (in thousands of dollars)....
a. What is the decision to be made, what is the chance event, and what is the consequence for this problem? How many decision alternatives are there? How many outcomes are there for the chance event?
b. Suppose that management of Myrtle Air Express believes that the probability of strong demand is .7 and the probability of weak demand is .3. Use the expected value approach to determine an optimal decision.
c. Suppose that the probability of strong demand is .8 and the probability of weak demand is .2. What is the optimal decision using the expected value approach?

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21.5 The distance from Potsdam to larger markets and limited air service have hindered the town in attracting new industry. Air Express, a major overnight delivery service, is considering establishing a regional distribution center in Potsdam. But Air Express will not establish the center unless the length of the runway at the local airport is increased. Anothercandidate for new development is Diagnostic Research, Inc. (DRI), a leading producer of medical testing equipment. DRI is considering building a new manufacturing plant. Increasing the length of the runway is not a requirement for DRI, but the planning commission feels that doing so will help convince DRI to locate their new plant in Potsdam Assuming that the town lengthens the runway, the Potsdam planning commission believes that the probabilities shown in the following table are applicable....For instance, the probability that Air Express will establish a distribution center and DRI will build a plant is .30.The estimated annual revenue to the town, after deducting the cost of lengthening the runway, is as follows:...If the runway expansion project is not conducted, the planning commission assesses the probability DRI will locate their new plant in Potsdam at .6; in this case, the estimated annual revenue to the town will be $450,000. If the runway expansion project is not conducted and DRI does not locate in Potsdam, the annual revenue will be $0 since no cost will have been incurred and no revenues will be forthcoming.
a. What is the decision to be made, what is the chance event, and what is the consequence?
b. Compute the expected annual revenue associated with the decision alternative to lengthen the runway.
c. Compute the expected annual revenue associated with the decision alternative to not lengthen the runway.
d. Should the town elect to lengthen the runway? Explain.
e. Suppose that the probabilities associated with lengthening the runway were as follows:...What effect, if any, would this change in the probabilities have on the recommended decision?

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21.6 Seneca Hill Winery recently purchased land for the purpose of establishing a new vineyard. Management is considering two varieties of white grapes for the new vineyard: Chardonnay and Riesling. The Chardonnay grapes would be used to produce a dry Chardonnay wine, and the Riesling grapes would be used to produce a semi-dry Riesling wine. It takes approximately four years from the time of planting before new grapes can be harvested. This length of time creates a great deal of uncertainty concerning future demand and makes the decision concerning the type of grapes to plant difficult. Three possibilities are being considered: Chardonnay grapes only; Riesling grapes only; and both Chardonnay and Riesling grapes. Seneca management decided that for planning purposes it would be adequate to consider only two demand possibilities for each type of wine: strong or weak. With two possibilities for each type of wine it was necessary to assess four probabilities. With the help of some forecasts in industry publications management made the following probability assessments....Revenue projections show an annual contribution to profit of $20,000 if Seneca Hill plants only Chardonnay grapes and demand is weak for Chardonnay wine, and $70,000 if they plant only Chardonnay grapes and demand is strong for Chardonnay wine. If they plant only Riesling grapes, the annual profit projection is $25,000 if demand is weak for Riesling grapes and $45,000 if demand is strong for Riesling grapes. If Seneca plants both types of grapes, the annual profit projections are shown in the following table....
a. What is the decision to be made, what is the chance event, and what is the consequence? Identify the alternatives for the decisions and the possible outcomes for the chance events.
b. Develop a decision tree.
c. Use the expected value approach to recommend which alternative Seneca Hill Winery should follow in order to maximize expected annual profit.
d. Suppose management is concerned about the probability assessments when demand for Chardonnay wine is strong. Some believe it is likely for Riesling demand to also be strong in this case. Suppose the probability of strong demand for Chardonnayand weak demand for Riesling is .05 and that the probability of strong demand for Chardonnay and strong demand for Riesling is .40. How does this change the recommended decision? Assume that the probabilities when Chardonnay demand is weakare still .05 and .50.
e. Other members of the management team expect the Chardonnay market to become saturated at some point in the future, causing a fall in prices. Suppose that the annual profit projections fall to $50,000 when demand for Chardonnay is strong and only Chardonnay grapes are planted. Using the original probability assessments, determine how this change would affect the optimal decision.

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21.7 The Lake Placid Town Council has decided to build a new community center to be used for conventions, concerts, and other public events, but considerable controversy surrounds the appropriate size. Many influential citizens want a large center that would be a showcase for the area, but the mayor feels that if demand does not support such a center, the community will lose a large amount of money. To provide structure for the decision process, the council narrowed the building alternatives to three sizes: small, medium, and large. Everybody agreed that the critical factor in choosing the best size is the number of people who will want to use the new facility. A regional planning consultant provided demand estimates under three scenarios: worst case, base case, and best case. The worst-case scenario corresponds to a situation in which tourism drops significantly; the base-case scenario corresponds to a situation in which Lake Placid continues to attract visitors at currentlevels; and the best-case scenario corresponds to a significant increase in tourism. The consultant has provided probability assessments of .10, .60, and .30 for the worst-case, basecase, and best-case scenarios, respectively.The town council suggested using net cash flow over a five-year planning horizon as the criterion for deciding on the best size. Aconsultant developed the following projections of net cash flow (in thousands of dollars) for a five-year planning horizon. All costs, including the consultant’s fee, are included....
a. What decision should Lake Placid make using the expected value approach?
b. Compute the expected value of perfect information. Do you think it would be worth trying to obtain additional information concerning which scenario is likely to occur?
c. Suppose the probability of the worst-case scenario increases to .2, the probability of the base-case scenario decreases to .5, and the probability of the best-case scenario remains at .3. What effect, if any, would these changes have on the decision recommendation?
d. The consultant suggested that an expenditure of $150,000 on a promotional campaign over the planning horizon will effectively reduce the probability of the worst-case scenario to zero. If the campaign can be expected to also increase the probability of the best-case scenario to .4, is it a good investment?

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21.8 Consider a variation of the PDC decision tree shown in Figure 19.5. As before, the company must first decide whether to undertake the market research study. If the market research study is conducted, the outcome will either be favorable (F) or unfavorable (U). However, for this exercise, assume there are only two decision alternatives d1 and d2 and two states of nature s1 and s2. The payoff table showing profit is as follows:...
a. Show the decision tree.
b. Use the following probabilities. What is the optimal decision strategy?
...
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21.9 A real estate investor has the opportunity to purchase land currently zoned residential. If the county board approves a request to rezone the property as commercial within the next year, the investor will be able to lease the land to a large discount firm that wants to open a new store on the property. However, if the zoning change is not approved, the investor will have to sell the property at a loss. Profits (in thousands of dollars) are shown in the following payoff table....
a. If the probability that the rezoning will be approved is .5, what decision is recommended? What is the expected profit?
b. The investor can purchase an option to buy the land. Under the option, the investor maintains the rights to purchase the land any time during the next three months while learning more about possible resistance to the rezoning proposal from area residents. Probabilities are as follows....What is the optimal decision strategy if the investor uses the option period to learn more about the resistance from area residents before making the purchase decision?
c. If the option will cost the investor an additional $10,000, should the investor purchase the option? Why or why not? What is the maximum that the investor should be willing to pay for the option?

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21.10 Dante Development Corporation is considering bidding on a contract for a new office building complex. Figure 19.9 shows the decision tree prepared by one of Dante’s analysts. At node 1, the company must decide whether to bid on the contract. The cost of preparing the bid is $200,000. The upper branch from node 2 shows that the company has a .8 probability of winning the contract if it submits a bid. If the company wins the bid, it will have to pay $2,000,000 to become a partner in the project. Node 3 shows that the company will then consider doing a market research study to forecast demand for the office units prior to beginning construction. The cost of this study is $150,000. Node 4 is a chance node showing the possible outcomes of the market research study.Nodes 5, 6, and 7 are similar in that they are the decision nodes for Dante to either build the office complex or sell the rights in the project to another developer. The decision to build the complex will result in an income of $5,000,000 if demand is high and $3,000,000 if demand is moderate. If Dante chooses to sell its rights in the project to another developer, incomefrom the sale is estimated to be $3,500,000. The probabilities shown at nodes 4, 8, and 9 are based on the projected outcomes of the market research study.
a. Verify Dante’s profit projections shown at the ending branches of the decision tree by calculating the payoffs of $2,650,000 and $650,000 for first two outcomes.
b. What is the optimal decision strategy for Dante, and what is the expected profit for this project?
c. What would the cost of the market research study have to be before Dante would change its decision about conducting the study?

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21.11 Hale’s TV Productions is considering producing a pilot for a comedy series in the hope of selling it to a major television network. The network may decide to reject the series, but it may also decide to purchase the rights to the series for either one or two years. At this point in time, Hale may either produce the pilot and wait for the network’s decision or transfer the rights for the pilot and series to a competitor for $100,000. Hale’s decision alternatives and profits (in thousands of dollars) are as follows:...The probabilities for the states of nature are P(s1) = .2, P(s2) = .3, and P(s3) = .5. For a consulting fee of $5000, an agency will review the plans for the comedy series and indicate the overall chances of a favorable network reaction to the series. Assume that the agency review will result in a favorable (F) or an unfavorable (U) review and that the following probabilities are relevant....
a. Construct a decision tree for this problem.
b. What is the recommended decision if the agency opinion is not used? What is the expected value?
c. What is the expected value of perfect information?
d. What is Hale’s optimal decision strategy assuming the agency’s information is used?
e. What is the expected value of the agency’s information?

f. Is the agency’s information worth the $5000 fee? What is the maximum that Hale should be willing to pay for the information?
g. What is the recommended decision?

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21.12 Martin’s Service Station is considering entering the snowplowing business for the coming winter season. Martin can purchase either a snowplow blade attachment for the station’s pick-up truck or a new heavy-duty snowplow truck. After analyzing the situation, Martin believes that either alternative would be a profitable investment if the snowfall is heavy. Smaller profits would result if the snowfall is moderate, and losses would result if the snowfall is light. The following profits/losses apply....The probabilities for the states of nature are P(s1) = .4, P(s2) = .3, and P(s3) = .3. Suppose that Martin decides to wait until September before making a final decision. Assessments of the probabilities associated with a normal (N) or unseasonably cold (U) September are as follows:...
a. Construct a decision tree for this problem.
b. What is the recommended decision if Martin does not wait until September? What is the expected value?
c. What is the expected value of perfect information?
d. What is Martin’s optimal decision strategy if the decision is not made until the September weather is determined? What is the expected value of this decision strategy?

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21.13 Lawson’s Department Store faces a buying decision for a seasonal product for which demand can be high, medium, or low. The purchaser for Lawson’s can order 1, 2, or 3 lots of the product before the season begins but cannot reorder later. Profit projections (in thousands of dollars) are shown....
a. If the prior probabilities for the three states of nature are .3, .3, and .4, respectively, what is the recommended order quantity?
b. At each preseason sales meeting, the vice president of sales provides a personal opinion regarding potential demand for this product. Because of the vice president’s enthusiasm and optimistic nature, the predictions of market conditions have always been either “xcellent” (E) or “very good” (V). Probabilities are as follows. What is the optimal decision strategy?
...c. Compute EVPI and EVSI. Discuss whether the firm should consider a consulting expert who could provide independent forecasts of market conditions for the product.

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21.14 Suppose that a decision analysis problem involves three possible states of nature: s1, s2, and s3. The prior probabilities are P(s1) = .2, P(s2) = .5, and P(s3) = .3. The sample information I has associated probabilities P(I|s1) = .1, P(I|s2) = .05, and P(I|s3) = .2. Compute the revised or posterior probabilities: P(s1|I ), P(s2|I ), and P(s3|I ).
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21.15 In the following profit payoff table for a decision problem with two states of nature and three decision alternatives, the prior probabilities for s1 and s2 are P(s1) = .8 and P(s2) = .2....a. What is the optimal decision?
b. Find the EVPI.
c. Suppose that sample information I is obtained, with P(I|s1) = .20 and P(I|s2) = .75. Find the posterior probabilities P(s1|I ) and P(s2|I). Recommend a decision alternative based on these probabilities.
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21.16 To save on expenses, Rona and Jerry agreed to form a carpool for traveling to and from work. Rona preferred to use the somewhat longer but more consistent Queen City Avenue. Although Jerry preferred the quicker expressway, he agreed with Rona that they should take Queen City Avenue if the expressway had a traffic jam. The following payoff table provides the one-way time estimate in minutes for traveling to and from work....Based on their experience with traffic problems, Rona and Jerry agreed on a .15 probability that the expressway would be jammed.In addition, they agreed that weather seemed to affect the traffic conditions on the expressway. Let...The following conditional probabilities apply....
a. Use Bayes’ theorem for probability revision to compute the probability of each weather condition and the conditional probability of the expressway open s1 or jammed s2 given each weather condition.
b. Show the decision tree for this problem.
c. What is the optimal decision strategy, and what is the expected travel time?

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21.17 The Gorman Manufacturing Company must decide whether to manufacture a component part at its Milan, Michigan, plant or purchase the component part from a supplier. The resulting profit is dependent upon the demand for the product. The following payoff table shows the projected profit (in thousands of dollars)....The state-of-nature probabilities are P(s1) = .35, P(s2) = .35, and P(s3) = .30.
a. Use a decision tree to recommend a decision.
b. Use EVPI to determine whether Gorman should attempt to obtain a better estimate of demand.
c. A test market study of the potential demand for the product is expected to report either a favorable (F) or unfavorable (U) condition. The relevant conditional probabilities are as follows:...What is the probability that the market research report will be favorable?
d. What is Gorman’s optimal decision strategy?
e. What is the expected value of the market research information?

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Solutions Statistics for Business and Economics 10 Ed. Anderson. Chapter 20

20.1 A process that is in control has a mean of μ = 12.5 and a standard deviation of σ = .8.
a. Construct the ... control chart for this process if samples of size 4 are to be used.
b. Repeat part (a) for samples of size 8 and 16.
c. What happens to the limits of the control chart as the sample size is increased? Discuss why this is reasonable.

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20.2 Twenty-five samples, each of size 5, were selected from a process that was in control. The sum of all the data collected was 677.5 pounds.
a. What is an estimate of the process mean (in terms of pounds per unit) when the process is in control?
b. Develop the ... control chart for this process if samples of size 5 will be used. Assume that the process standard deviation is .5 when the process is in control, and that the mean of the process is the estimate developed in part (a).

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20.3 Twenty-five samples of 100 items each were inspected when a process was considered to be operating satisfactorily. In the 25 samples, a total of 135 items were found to be defective.
a. What is an estimate of the proportion defective when the process is in control?
b. What is the standard error of the proportion if samples of size 100 will be used for statistical process control?
c. Compute the upper and lower control limits for the control chart.

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20.4 A process sampled 20 times with a sample of size 8 resulted in ... and .... Compute the upper and lower control limits for the and R charts for this process.
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20.5 Temperature is used to measure the output of a production process. When the process is in control, the mean of the process is μ = 128.5 and the standard deviation is σ = .4.
a. Construct the chart for this process if samples of size 6 are to be used.
b. Is the process in control for a sample providing the following data?...
c. Is the process in control for a sample providing the following data?...

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20.6 A quality control process monitors the weight per carton of laundry detergent. Control limits are set at UCL = 20.12 ounces and LCL = 19.90 ounces. Samples of size 5 are used for the sampling and inspection process. What are the process mean and process standard deviation for the manufacturing operation?
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20.7 The Goodman Tire and Rubber Company periodically tests its tires for tread wear under simulated road conditions. To study and control the manufacturing process, 20 samples, each containing three radial tires, were chosen from different shifts over several days of operation, with the following results. Assuming that these data were collected when the manufacturing process was believed to be operating in control, develop the R and ... charts....
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20.8 Over several weeks of normal, or in-control, operation, 20 samples of 150 packages each of synthetic-gut tennis strings were tested for breaking strength. A total of 141 packages of the 3000 tested failed to conform to the manufacturer’s specifications.
a. What is an estimate of the process proportion defective when the system is in control?
b. Compute the upper and lower control limits for a p chart.
c. With the results of part (b), what conclusion should be made about the process if tests on a new sample of 150 packages find 12 defective? Do there appear to be assignable causes in this situation?
d. Compute the upper and lower control limits for an np chart.
e. Answer part (c) using the results of part (d).

f. Which control chart would be preferred in this situation? Explain.

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20.9 An automotive industry supplier produces pistons for several models of automobiles. Twenty samples, each consisting of 200 pistons, were selected when the process was known to be operating correctly. The numbers of defective pistons found in the samples follow....
a. What is an estimate of the proportion defective for the piston manufacturing process when it is in control?
b. Construct the p chart for the manufacturing process, assuming each sample has 200 pistons.
c. With the results of part (b), what conclusion should be made if a sample of 200 has 20 defective pistons?
d. Compute the upper and lower control limits for an np chart.
e. Answer part (c) using the results of part (d).

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20.10 For an acceptance sampling plan with n = 25 and c = 0, find the probability of accepting a lot that has a defect rate of 2%. What is the probability of accepting the lot if the defect rate is 6%?
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20.11 Consider an acceptance sampling plan with n = 20 and c = 0. Compute the producer’s risk for each of the following cases.
a. The lot has a defect rate of 2%.
b. The lot has a defect rate of 6%.

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20.12 Repeat exercise 11 for the acceptance sampling plan with n = 20 and c = 1. What happens to the producer’s risk as the acceptance number c is increased? Explain.
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20.13 Refer to the KALI problem presented in this section. The quality control manager requested a producer’s risk of .10 when p0 was .03 and a consumer’s risk of .20 when p1 was .15. Consider the acceptance sampling plan based on a sample size of 20 and an acceptance number of 1. Answer the following questions.
a. What is the producer’s risk for the n = 20, c = 1 sampling plan?
b. What is the consumer’s risk for the n = 20, c = 1 sampling plan?
c. Does the n = 20, c = 1 sampling plan satisfy the risks requested by the quality control manager? Discuss.

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20.14 To inspect incoming shipments of raw materials, a manufacturer is considering samples of sizes 10, 15, and 20. Use binomial probabilities to select a sampling plan that provides a producer’s risk of α = .03 when p0 is .05 and a consumer’s risk of β = .12 when p1 is .30.
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20.15 A domestic manufacturer of watches purchases quartz crystals from a Swiss firm. The crystals are shipped in lots of 1000. The acceptance sampling procedure uses 20 randomly selected crystals.
a. Construct operating characteristic curves for acceptance numbers of 0, 1, and 2.
b. If p0 is .01 and p1 = .08, what are the producer’s and consumer’s risks for each sampling plan in part (a)?

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20.16 Samples of size 5 provided the following 20 sample means for a production process that is believed to be in control....
a. Based on these data, what is an estimate of the mean when the process is in control?
b. Assume that the process standard deviation is σ = .50. Develop the ... control chart for this production process. Assume that the mean of the process is the estimate developed in part (a).
c. Do any of the 20 sample means indicate that the process was out of control?

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20.17 Product filling weights are normally distributed with a mean of 350 grams and a standard deviation of 15 grams.
a. Develop the control limits for the ...chart for samples of size 10, 20, and 30.
b. What happens to the control limits as the sample size is increased?
c. What happens when a Type I error is made?
d. What happens when a Type II error is made?
e. What is the probability of a Type I error for samples of size 10, 20, and 30?
f. What is the advantage of increasing the sample size for control chart purposes? What error probability is reduced as the sample size is increased?

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20.18 Twenty-five samples of size 5 resulted in ... and .... Compute control limits for the ... and R charts, and estimate the standard deviation of the process.
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20.19 The following are quality control data for a manufacturing process at Kensport Chemical Company. The data show the temperature in degrees centigrade at five points in time during a manufacturing cycle. The company is interested in using control charts to monitor the temperature of its manufacturing process. Construct the chart and R chart. What conclusions can be made about the quality of the process?...
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20.20 The following were collected for the Master Blend Coffee production process. The data show the filling weights based on samples of 3-pound cans of coffee. Use these data to construct the ... and R charts. What conclusions can be made about the quality of the production process?...
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20.21 Consider the following situations. Comment on whether the situation might cause concern about the quality of the process.
a. A p chart has LCL = 0 and UCL = .068. When the process is in control, the proportion defective is .033. Plot the following seven sample results: .035, .062, .055, .049, .058, .066, and .055. Discuss.
b. An chart has LCL = 22.2 and UCL = 24.5. The mean is μ = 23.35 when the process is in control. Plot the following seven sample results: 22.4, 22.6, 22.65, 23.2, 23.4, 23.85, and 24.1. Discuss.

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20.22 Managers of 1200 different retail outlets make twice-a-month restocking orders from a central warehouse. Past experience shows that 4% of the orders result in one or more errors such as wrong item shipped, wrong quantity shipped, and item requested but not shipped. Random samples of 200 orders are selected monthly and checked for accuracy.
a. Construct a control chart for this situation.
b. Six months of data show the following numbers of orders with one or more errors: 10, 15, 6, 13, 8, and 17. Plot the data on the control chart. What does your plot indicate about the order process?

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20.23 An n = 10, c = 2 acceptance sampling plan is being considered; assume that p0 = .05 and p1 = .20.
a. Compute both producer’s and consumer’s risk for this acceptance sampling plan.
b. Would the producer, the consumer, or both be unhappy with the proposed sampling plan?
c. What change in the sampling plan, if any, would you recommend?

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20.24 An acceptance sampling plan with n = 15 and c = 1 has been designed with a producer’s risk of .075.
a. Was the value of p0 .01, .02, .03, .04, or .05? What does this value mean?
b. What is the consumer’s risk associated with this plan if p1 is .25?

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20.25 Amanufacturer produces lots of a canned food product. Let p denote the proportion of the lots that do not meet the product quality specifications. An n = 25, c = 0 acceptance sampling plan will be used.
a. Compute points on the operating characteristic curve when p = .01, .03, .10, and .20.
b. Plot the operating characteristic curve.
c. What is the probability that the acceptance sampling plan will reject a lot containing .01 defective?

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Solutions Statistics for Business and Economics 10 Ed. Anderson. Chapter 19

19.1
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19.8
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19.11
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19.12 Two fuel additives are tested to determine their effect on miles per gallon for passenger cars. Test results for 12 cars follow; each car was tested with both fuel additives. Use α = .05 and the Wilcoxon signed rank test to see whether there is a significant difference in the additives....
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19.13
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19.14
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19.15 A test was conducted of two overnight mail delivery services. Two samples of identical deliveries were set up so that both delivery services were notified of the need for a delivery at the same time. The hours required to make each delivery follow. Do the data shown suggest a difference in the delivery times for the two services? Use a .05 level of significance for the test....
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19.16
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19.17
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19.18 Two fuel additives are being tested to determine their effect on gas mileage. Seven cars were tested with additive 1 and nine cars were tested with additive 2. The following data show the miles per gallon obtained with the two additives. Use α = .05 and the MWW rank sum test to see whether there is a significant difference in gasoline mileage for the two additives....
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19.19
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19.20
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19.21
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19.22
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19.23 The Police records show the following numbers of daily crime reports for a sample of days during the winter months and a sample of days during the summer months. Use a .05 level of significance to determine whether there is a significant difference between the winter and summer months in terms of the number of crime reports....
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19.24 The A certain brand of microwave oven was priced at 10 stores in Dallas and 13 stores in San Antonio. The data follow. Use a .05 level of significance and test whether prices for the microwave oven are the same in the two cities....
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19.25
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19.26
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19.27 The Three admission test preparation programs are being evaluated. The scores obtained by a sample of 20 people who used the test preparation programs provided the following data. Use the Kruskal-Wallis test to determine whether there is a significant difference among the three test preparation programs. Use α = .01....
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19.28 The Forty-minute workouts of one of the following activities three days a week will lead to a loss of weight. The following sample data show the number of calories burned during 40-minute workouts for three different activities. Do these data indicate differences in the amount of calories burned for the three activities? Use a .05 level of significance. What is your conclusion?...
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19.29 The Conde Nast Traveler magazine conducts an annual survey of its readers in order to rate the top 80 cruise ships in the world (Conde Nast Traveler, February 2006). With 100 the highest possible rating, the overall ratings for a sample of ships from the Holland America, Princess, and Royal Caribbean cruise lines are shown here. Use the Kruskal-Wallis test with α = .05 to determine whether the overall ratings among the three cruise lines differ significantly....
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19.30
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19.31 The The better-selling candies are high in calories. Assume that the following data show the calorie content from samples of M&Ms, Kit Kat, and Milky Way II. Test for significant differences in the calorie content of these three candies. At a .05 level of significance, what is your conclusion?...
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19.32 The Consider the following set of rankings for a sample of 10 elements....
a. Compute the Spearman rank correlation coefficient for the data.
b. Use α = .05 and test for significant rank correlation. What is your conclusion?

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19.33 The Consider the following two sets of rankings for six items....Note that in the first case the rankings are identical, whereas in the second case the rankings are exactly opposite. What value should you expect for the Spearman rank correlation coefficient for each of these cases? Explain. Calculate the rank correlation coefficient for each case.
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19.34
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19.35 The A national study by Harris Interactive, Inc., evaluated the top Internet companies and their reputations (The Wall Street Journal, November 18, 1999). The following two lists show how 10 Internet companies ranked in terms of reputation and percentage of respondents who said they would purchase the company’s stock. A positive rank correlation is anticipated because it seems reasonable to expect that a company with a higher reputation would be a more desirable purchase....
a. Compute the rank correlation between reputation and probable purchase.
b. Test for a significant positive rank correlation. What is the p-value?
c. At α = .05, what is your conclusion?

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19.36 The The rankings of a sample of professional golfers in both driving distance and putting follows. What is the rank correlation between driving distance and putting? Use a .10 level of significance....
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19.37 The A student organization surveyed both recent graduates and current students to obtain information on the quality of teaching at a particular university. An analysis of the responses provided the following teaching-ability rankings. Do the rankings given by the current students agree with the rankings given by the recent graduates? Use α = .10 and test for a significant rank correlation....
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19.38 The A survey asked the following question: Do you favor or oppose providing tax-funded vouchers or tax deductions to parents who send their children to private schools? Of the 2010 individuals surveyed, 905 favored the support, 1045 opposed the support, and 60 offered no opinion. Do the data indicate a significant difference in the preferences for the support for parents who send their children to private schools? Use a .05 level of significance.
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19.39
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19.40
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19.41 A study was designed to evaluate the weight-gain potential of a new poultry feed. A sample of 12 chickens was used in a six-week study. The weight of each chicken was recorded before and after the six-week test period. The differences between the before and after weights of the 12 chickens are 1.5, 1.2, −.2, .0, .5, .7, .8, 1.0, .0, .6, .2, −.01. A negative value indicates a weight loss during the test period, whereas .0 indicates no weight change over the period. Use a .05 level of significance to determine whether the new feed appears to provide a weight gain for the chickens.
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19.42 The following data are product weights for items produced on two production lines. Test for a difference between the product weights for the two lines. Use a = .10....
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19.43 A client wants to determine whether there is a significant difference in the time required to complete a program evaluation with the three different methods that are in common use. The times (in hours) required for each of 18 evaluators to conduct a program evaluation follow....Use α = .05 and test to see whether there is a significant difference in the time required by the three methods.
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19.44 A sample of 20 engineers employed with a company for three years has been rank-ordered with respect to managerial potential. Some of the engineers attended the company’s management-development course, others attended an off-site management-development program at a local university, and the remainder did not attend any program. Use the following rankings and a = .025 to test for a significant difference in the managerial potential of the three groups....
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19.45
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19.46 A sample of 15 students received the following rankings on midterm and final examinations in a statistics course....Compute the Spearman rank correlation coefficient for the data and test for a significant correlation. Use α = .10.
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Solutions Statistics for Business and Economics 10 Ed. Anderson. Chapter 18

18.1
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18.2
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18.3
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18.4
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18.5
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18.6
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18.7
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18.8
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18.10
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18.11
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18.18
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18.24
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18.27
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18.28
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18.30
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18.34
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18.36
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18.38
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18.43
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Solutions Statistics for Business and Economics 10 Ed. Anderson. Chapter 17

17.1
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17.3
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17.4
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17.5 Under the last-in first-out (LIFO) inventory valuation method, a price index for inventory must be established for tax purposes. The quantity weights are based on year-ending inventory levels. Use the beginning-of-the-year price per unit as the base-period price and develop a weighted aggregate index for the total inventory value at the end of the year. What type of weighted aggregate price index must be developed for the LIFO inventory valuation?...
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17.6 Price relatives for three items, along with base-period prices and usage are shown in the following table. Compute a weighted aggregate price index for the current period....
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17.7 The Mitchell Chemical Company produces a special industrial chemical that is a blend of three chemical ingredients. The beginning-year cost per pound, the ending-year cost per pound, and the blend proportions follow....
a. Compute the price relatives for the three ingredients.
b. Compute a weighted average of the price relatives to develop a one-year cost index for raw materials used in the product. What is your interpretation of this index value?

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17.8 An investment portfolio consists of four stocks. The purchase price, current price, and number of shares are reported in the following table....Construct a weighted average of price relatives as an index of the performance of the portfolio to date. Interpret this price index.
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17.9 Compute the price relatives for the R&B Beverages products in exercise 4. Use a weighted average of price relatives to show that this method provides the same index as the weighted aggregate method.
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17.10
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17.11 Average hourly wages for workers in service industries for the four years from 2002 through 2005 are reported here. Use the Consumer Price Index information provided to deflate the wages series. Calculate the percentage increase or decrease in real wages and salaries from 2003 to 2005....
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17.12
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17.13
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17.14
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17.15
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17.16
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17.17
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17.18
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17.19
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17.20
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17.21
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17.22
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17.23
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17.24 Starting faculty salaries (nine-month basis) for assistant professors of business administration at a major Midwestern university follow. Use the CPI to deflate the salary data to constant dollars. Comment on the trend in salaries in higher education as indicated by these data....
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17.25
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17.26
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Solutions Statistics for Business and Economics 10 Ed. Anderson. Chapter 16

16.1 Consider the following data for two variables, x and y....
a. Develop an estimated regression equation for the data of the form ŷ = b0 + b1x.
b. Using the results from part (a), test for a significant relationship between x and y; use α = .05.
c. Develop a scatter diagram for the data. Does the scatter diagram suggest an estimated regression equation of the form ŷ = b0 + b1x + b2x2? Explain.
d. Develop an estimated regression equation for the data of the form ŷ = b0 + b1x + b2x2.
e. Refer to part (d). Is the relationship between x, x2, and y significant? Use α = .05.

f. Predict the value of y when x = 25.

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16.2 Consider the following data for two variables, x and y....
a. Develop an estimated regression equation for the data of the form ŷ = b0+ b1x. Comment on the adequacy of this equation for predicting y.
b. Develop an estimated regression equation for the data of the form ŷ = b0 + b1x + b2x2. Comment on the adequacy of this equation for predicting y.
c. Predict the value of y when x = 20.

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16.3 Consider the following data for two variables, x and y....
a. Does there appear to be a linear relationship between x and y? Explain.
b. Develop the estimated regression equation relating x and y.
c. Plot the standardized residuals versus y for the estimated regression equation developed in part (b). Do the model assumptions appear to be satisfied? Explain.
d. Perform a logarithmic transformation on the dependent variable y. Develop an estimated regression equation using the transformed dependent variable. Do the model assumptions appear to be satisfied by using the transformed dependent variable? Does a reciprocal transformation work better in this case? Explain.

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16.4 A highway department is studying the relationship between traffic flow and speed. The following model has been hypothesized....Where...The following data were collected during rush hour for six highways leading out of the city.
a. Develop an estimated regression equation for the data.
b. Using α = .01, test for a significant relationship.

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16.5 In working further with the problem of exercise 4, statisticians suggested the use of the following curvilinear estimated regression equation....
a. Use the data of exercise 4 to compute the coefficients of this estimated regression equation.
b. Using α = .01, test for a significant relationship.
c. Estimate the traffic flow in vehicles per hour at a speed of 38 miles per hour.

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16.6 A study of emergency service facilities investigated the relationship between the number of facilities and the average distance traveled to provide the emergency service. The following table gives the data collected....
a. Develop a scatter diagram for these data, treating average distance traveled as the dependent variable.
b. Does a simple linear model appear to be appropriate? Explain.
c. Develop an estimated regression equation for the data that you believe will best explain the relationship between these two variables.

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16.7
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16.8 Corvette, Ferrari, and Jaguar produced a variety of classic cars that continue to increase in value. The following data, based upon the Martin Rating System for Collectible Cars, show the rarity rating (1–20) and the high price ($1000) for 15 classic cars (http:// www.businessweek.com, February 2006)....
a. Develop a scatter diagram of the data using the rarity rating as the independent variable and price as the independent variable. Does a simple linear regression model appear to be appropriate?
b. Develop an estimated multiple regression equation with x = rarity rating and x2 as the two independent variables.
c. Consider the nonlinear relationship shown by equation (16.7). Use logarithms to develop an estimated regression equation for this model.
d. Do you prefer the estimated regression equation developed in part (b) or part (c)? Explain.

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16.9
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16.10 In a regression analysis involving 27 observations, the following estimated regression equation was developed....For this estimated regression equation SST = 1550 and SSE = 520.
a. At α = .05, test whether x1 is significant.Suppose that variables x2 and x3 are added to the model and the following regression equation is obtained....For this estimated regression equation SST = 1550 and SSE = 100.
b. Use an F test and a .05 level of significance to determine whether x2 and x3 together contribute significantly to the model.

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16.11 In a regression analysis involving 30 observations, the following estimated regression equation was obtained....For this estimated regression equation SST = 1805 and SSR = 1760.
a. At α = .05, test the significance of the relationship among the variables.Suppose variables x1 and x4 are dropped from the model and the following estimated regression equation is obtained....For this model SST = 1805 and SSR = 1705.
b. Compute SSE(x1, x2, x3, x4).
c. Compute SSE(x2, x3).
d. Use an F test and a .05 level of significance to determine whether x1 and x4 contribute significantly to the model.

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16.12 The Ladies Professional Golfers Association (LPGA) maintains statistics on performance and earnings for members of the LPGA Tour. Year-end performance statistics for the 30 players who had the highest total earnings in LPGA Tour events for 2005 appear on the data disk in the file named LPGATour (http://www.lpga.com, 2006). Earnings ($1000) is the total earnings in thousands of dollars; Scoring Avg. is the average score for all events; Greens in Reg. is the percentage of time a player is able to hit the green in regulation; Putting Avg. is the average number of putts taken on greens hit in regulation; and Sand Saves is the percentage of time a player is able to get “up and down” once in a greenside sand bunker. A green is considered hit in regulation if any part of the ball is touching the putting surface and the difference between the value of par for the hole and the number of strokes taken to hit the green is at least 2.
a. Develop an estimated regression equation that can be used to predict the average score for all events given the average number of putts taken on greens hit in regulation.
b. Develop an estimated regression equation that can be used to predict the average score for all events given the percentage of time a player is able to hit the green in regulation, the average number of putts taken on greens hit in regulation, and the percentage of time a player is able to get “up and down” once in a greenside sand bunker.
c. At the .05 level of significance, test whether the two independent variables added in part (b), the percentage of time a player is able to hit the green in regulation and the percentage of time a player is able to get “up and down” once in a greenside sand bunker, contribute significantly to the estimated regression equation developed in part (a). Explain.

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16.13 Refer to exercise 12.
a. Develop an estimated regression equation that can be used to predict the total earnings for all events given the average number of putts taken on greens hit in regulation.
b. Develop an estimated regression equation that can be used to predict the total earnings for all events given the percentage of time a player is able to hit the green in regulation, the average number of putts taken on greens hit in regulation, and the percentage of time a player is able to get “up and down” once in a greenside sand bunker.
c. At the .05 level of significance, test whether the two independent variables added in part (b), the percentage of time a player is able to hit the green in regulation and the percentage of time a player is able to get “up and down” once in a greenside sand bunker, contribute significantly to the estimated regression equation developed in part (a). Explain.
d. In general, lower scores should lead to higher earnings. To investigate this option to predicting total earnings, develop an estimated regression equation that can be used to predict total earnings for all events given the average score for all events. Would you prefer to use this equation to predict total earnings or the estimated regression equation developed in part (b)? Explain.

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16.14 A 10-year study conducted by the American Heart Association provided data on how age, systolic blood pressure, and smoking relate to the risk of strokes. Data from a portion of this study follow. Risk is interpreted as the probability (times 100) that a person will have a stroke over the next 10-year period. For the smoker variable, 1 indicates a smoker and 0 indicates a nonsmoker.......
a. Develop an estimated regression equation that can be used to predict the risk of stroke given the age and blood-pressure level.
b. Consider adding two independent variables to the model developed in part (a), one for the interaction between age and blood-pressure level and the other for whether the person is a smoker. Develop an estimated regression equation using these four independent variables.
c. At a .05 level of significance, test to see whether the addition of the interaction term and the smoker variable contribute significantly to the estimated regression equation developed in part (a).

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16.15
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16.16 A study provided data on variables that may be related to the number of weeks a manufacturing worker has been jobless. The dependent variable in the study (Weeks) was defined as the number of weeks a worker has been jobless due to a layof
f. The following independent variables were used in the study....The data are available on the CD that accompanies this text in the file named Layoffs.
a. Develop the best one-variable estimated regression equation.
b. Use the stepwise procedure to develop the best estimated regression equation. Use values of .05 for p-value to Enter and p-value to Leave.
c. Use the forward selection procedure to develop the best estimated regression equation. Use a value of .05 for p-value to Enter.
d. Use the backward elimination procedure to develop the best estimated regression equation. Use a value of .05 for p-value to Leave.

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16.17 The Ladies Professional Golfers Association (LPGA) maintains statistics on performance and earnings for members of the LPGA Tour. Year-end performance statistics for the 30 players who had the highest total earnings in LPGA Tour events for 2005 appear on the data disk in the file named LPGATour2 (http://www.lpga.com, 2006). Earnings ($1000) is the total earnings in thousands of dollars; Scoring Avg. is the average score for all events; Drive Average is the average length of a players drive in yards; Greens in Reg. is the percentage of time a player is able to hit the green in regulation; Putting Avg. is the average number of putts taken on greens hit in regulation; and Sand Saves is the percentage of time a player is able to get “up and down” once in a greenside sand bunker. A green is considered hit in regulation if any part of the ball is touching the putting surface and the difference between the value of par for the hole and the number of strokes taken to hit the green is at least 2. Let DriveGreens denote a new independent variable that represents the interaction between the average length of a player’s drive and the percentage of time a player is able to hit the green in regulation. Use the methods in this section to develop the best estimated multiple regression equation for estimating a player’s average score for all events.
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16.18 Jeff Sagarin has been providing sports ratings for USA Today since 1985. In baseball his predicted RPG (runs/game) statistic takes into account the entire player’s offensive statistics, and is claimed to be the best measure of a player’s true offensive value. The following data show the RPG and a variety of offensive statistics for the 2005 Major League Baseball (MLB) season for 20 members of the New York Yankees (http://www.usatoday.com, March 3, 2006). The labels on columns are defined as follows: RPG, predicted runs per game statistic; H, hits; 2B, doubles; 3B, triples; HR, home runs; RBI, runs batted in; BB, bases on balls (walks); SO, strikeouts; SB, stolen bases; CS, caught stealing; OBP, on-base percentage; SLG, slugging percentage; and AVG, batting average....Let the dependent variable be the RPG statistic.
a. Develop the best one-variable estimated regression equation.
b. Use the methods in this section to develop the best estimated multiple regression equation for estimating a player’s RPG.

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16.19 Refer to exercise 14. Using age, blood pressure, whether a person is a smoker, and any interaction involving those variables, develop an estimated regression equation that can be used to predict risk. Briefly describe the process you used to develop an estimated regression equation for these data.
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16.20 Consider a completely randomized design involving four treatments: A, B, C, and D. Write a multiple regression equation that can be used to analyze these data. Define all variables.
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16.21 Consider a completely randomized design involving four treatments: A, B, C, and D. Write a multiple regression equation that can be used to analyze these data. Define all variables.
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16.22 Write a multiple regression equation that can be used to analyze the data for a two-factorial design with two levels for factor A and three levels for factor B. Define all variables.
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16.23 The Jacobs Chemical Company wants to estimate the mean time (minutes) required to mix a batch of material on machines produced by three different manufacturers. To limit the cost of testing, four batches of material were mixed on machines produced by each of the three manufacturers. The times needed to mix the material follow....
a. Write a multiple regression equation that can be used to analyze the data.
b. What are the best estimates of the coefficients in your regression equation?
c. In terms of the regression equation coefficients, what hypotheses must we test to see whether the mean time to mix a batch of material is the same for all three manufacturers?d. For an α = .05 level of significance, what conclusion should be drawn?

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16.24 Four different paints are advertised as having the same drying time. To check the manufacturers’ claims, five samples were tested for each of the paints. The time in minutes until the paint was dry enough for a second coat to be applied was recorded for each sample. The data obtained follow....
a. Use α = .05 to test for any significant differences in mean drying time among the paints.
b. What is your estimate of mean drying time for paint 2? How is it obtained from the computer output?

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16.25 An automobile dealer conducted a test to determine whether the time needed to complete a minor engine tune-up depends on whether a computerized engine analyzer or an electronic analyzer is used. Because tune-up time varies among compact, intermediate, and full-sized cars, the three types of cars were used as blocks in the experiment. The data (time in minutes) obtained follow....Use α = .05 to test for any significant differences.
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16.26 A mail-order catalog firm designed a factorial experiment to test the effect of the size of a magazine advertisement and the advertisement design on the number (in thousands) of catalog requests received. Three advertising designs and two sizes of advertisements were considered. The following data were obtained. Test for any significant effects due to type of design, size of advertisement, or interaction. Use α = .05....
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16.27 The following data show the daily closing prices (in dollars per share) for IBM for November 3, 2005, through December 1, 2005 (Compustat, February 26, 2006)....
a. Define the independent variable Period, where Period = 1 corresponds to the data for November 3, Period = 2 corresponds to the data for November 4, and so on. Develop the estimated regression equation that can be used to predict the closing price given the value of Period.
b. At the .05 level of significance, test for any positive autocorrelation in the data.

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16.28 Refer to the Cravens data set in Table 16.5. In Section 16.3 we showed that the estimated regression equation involving Accounts, AdvExp, Poten, and Share had an adjusted coefficient of determination of 88.1%. Use the .05 level of significance and apply the Durbin-Watson test to determine whether positive autocorrelation is present.
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16.29 Lower prices for color laser printers make them a great alternative to inkjet printers. PC World reviewed and rated 10 color laser printers. The following data show the price, printing speed for color graphics in pages per minute (ppm), and the overall PC World rating for each printer tested (PC World, December 2005)....
a. Develop a scatter diagram of the data using the printing speed as the independent variable. Does a simple linear regression model appear to be appropriate?
b. Develop an estimated multiple regression equation with x = speed and x2 as the two independent variables.
c. Consider the nonlinear model shown by equation (16.7). Use logarithms to transform this nonlinear model into an equivalent linear model, and develop the corresponding estimated regression equation. Does the estimated regression equation provide a better fit than the estimated regression equation developed in part (b)?

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16.30
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16.31 A study investigated the relationship between audit delay (Delay), the length of time from a company’s fiscal year-end to the date of the auditor’s report, and variables that describe the client and the auditor. Some of the independent variables that were included in this study follow....A sample of 40 companies provided the following data.......
a. Develop the estimated regression equation using all of the independent variables.
b. Did the estimated regression equation developed in part (a) provide a good fit? Explain.
c. Develop a scatter diagram showing Delay as a function of Finished. What does this scatter diagram indicate about the relationship between Delay and Finished?
d. On the basis of your observations about the relationship between Delay and Finished, develop an alternative estimated regression equation to the one developed in (a) to explain as much of the variability in Delay as possible.

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16.32 Refer to the data in exercise 30. Consider a model in which only Industry is used to predict Delay. At a .01 level of significance, test for any positive autocorrelation in the data.
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16.33 Refer to the data in exercise 30.
a. Develop an estimated regression equation that can be used to predict Delay by using Industry and Quality.
b. At the .05 level of significance, test for any positive autocorrelation in the data.

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16.34 A study was conducted to investigate browsing activity by shoppers. Shoppers were classified as nonbrowsers, light browsers, and heavy browsers. For each shopper in the study, a measure was obtained to determine how comfortable the shopper was in the store. Higher scores indicated greater comfort. Assume that the following data are from this study. Use a .05 level of significance to test for differences in comfort levels among the three types of browsers....
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16.35 Money magazine reported price and related data for 418 of the most popular vehicles of the 2003 model year. One of the variables reported was the vehicle’s resale value, expressed as a percentage of the manufacturer’s suggested resale price. The data were classified according to size and type of vehicle. The following table shows the resale value for 10 randomly selected small cars, 10 randomly selected midsize cars, 10 randomly selected luxury cars, and 10 randomly selected sports cars (Money, March 2003)....Use α = .05 and test for any significant difference in the mean resale value among the four types of vehicles.
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