A study was conducted to compare the salaries of accounting clerks and data entry operators. One of the hypotheses to be tested is that the variability of salaries among accounting clerks is the same as the variability of salaries of data entry operators. To test this hypothesis, a random sample of 16 accounting clerks was taken, resulting in a sample mean salary of $34,526 and a sample standard deviation of $1,200. A random sample of 14 data entry operators was taken as well, resulting in a sample mean of $31,895 and a sample standard deviation of $1,050. Use these data and α = .05 to test to determine whether the population variance of salaries is the same for accounting clerks as it is for data entry operators. Assume that salaries of data entry operators and accounting clerks are normally distributed in the population.
> The following data were gathered from a randomized block design. Use α = .01 to test for a significant difference in the treatment levels. Establish the hypotheses and reach a conclusion about the null hypothesis.
> Use ANOVA to analyze the data from the randomized block design given here. Let α = .05. State the null and alternative hypotheses and determine whether the null hypothesis is rejected.
> Problem 11.16 analyzed the number of weekly hours worked per person at five different plants. An F value of 3.10 was obtained with a probability of .0266. Because the probability is less than .05, the null hypothesis is rejected at α = .05.
> Do multiple comparisons on the data in Problem 11.14 using Tukey’s HSD test and α = .05. State which pairs of cities, if any, have significantly different mean costs.
> Using α = .05, compute critical values using the Tukey-Kramer procedure for the pairwise groups in Problem 11.13. Determine which pairs of groups are significantly different, if any.
> Use Tukey’s HSD test to compute multiple comparisons for the data in Problem 11.12. Let α = .01. State which regions, if any, are significantly different from other regions in mean starting salary figures.
> Use the Tukey-Kramer procedure to do multiple comparisons for Problem 11.11. Let α = .01. State which pairs of machines, if any, produce significantly different mean fills.
> Using Problem 11.8, compute Tukey’s HSD and determine whether there is a significant difference in means by using this methodology. Let α = .05.
> Using the results from Problem 11.7, compute a Tukey’s HSD to determine whether there are any significant differences between group means. Let α = .01.
> Suppose a random sample of 85 items has been taken from a population and 40 of the items contain the characteristic of interest. Use this information to calculate a 90% confidence interval to estimate the proportion of the population that has the charact
> Use the Tukey-Kramer procedure to determine whether there is a significant difference between the means of groups 2 and 5 in Problem 11.6. Let α = .01.
> Southwest Airlines is able to keep fares low, in part because of relatively low maintenance costs on its airplanes. One of the main reasons for the low maintenance costs is that Southwest flies only one type of aircraft, the Boeing 737. However, Southwes
> Using the results of Problem 11.5, compute a critical value by using the Tukey-Kramer procedure for groups 1 and 2. Use α = .05. Determine whether there is a significant difference between these two groups.
> A completely randomized design has been analyzed by using a one-way ANOVA. There are four treatment groups in the design, and each sample size is six. MSE is equal to 2.389. Using α = .05, compute Tukey’s HSD for this ANOVA.
> Suppose an ANOVA has been performed on a completely randomized design containing six treatment levels. The mean for group 3 is 15.85, and the sample size for group 3 is eight. The mean for group 6 is 17.21, and the sample size for group 6 is seven. MSE i
> Business is very good for a chemical company. In fact, it is so good that workers are averaging more than 40 hours per week at each of the chemical company’s five plants. However, management is not certain whether there is a difference
> Shown here is the Minitab output for a one-way ANOVA. Analyze the results. Include the number of treatment levels, the sample sizes, the F value, the overall statistical significance of the test, and the values of the means. Analysis of Variance Means
> Family transportation costs are usually higher than most people believe because those costs include car payments, insurance, fuel costs, repairs, parking, and public transportation. Twenty randomly selected families in four major cities are asked to use
> A management consulting company presents a three-day seminar on project management to various clients. The seminar is basically the same each time it is given. However, sometimes it is presented to high-level managers, sometimes to midlevel managers, and
> That the starting salaries of new accounting graduates would differ according to geographic regions of the United States seems logical. A random selection of accounting firms is taken from three geographic regions, and each is asked to state the starting
> Use the following sample information to calculate the confidence interval to estimate the population proportion. Let x be the number of items in the sample having the characteristic of interest. a) n = 116 and x = 57, with 99% confidence b) n = 800 and x
> A milk company has four machines that fill gallon jugs with milk. The quality-control manager is interested in determining whether the average fill for these machines is the same. The following data represent random samples of fill measures (in quarts) f
> Suppose you are using a completely randomized design to study some phenomenon. There are three treatment levels and a total of 17 people in the study. Complete the following ANOVA table. Use α = .05 to find the table F value and use the dat
> Some New York Stock Exchange analysts believe that 24-hour trading on the stock exchange is the wave of the future. As an initial test of this idea, the New York St Exchange opened two after-hour “crossing sections” in the early 1990s and studied the res
> Employee suggestions can provide useful and insightful ideas for management. Some companies solicit and receive employee suggestions more than others, and company culture influences the use of employee suggestions. Suppose a study is conducted to determi
> Suppose a market analyst wants to determine the difference in the average price of a gallon of whole milk in Seattle and Atlanta. To do so, he takes a telephone survey of 21 randomly selected consumers in Seattle who have purchased a gallon of milk and a
> A manufacturing company produces plastic pipes that are specified to be 10 inches long and 1/8 inch thick with an opening of 3/4 inch. These pipes are molded on two different machines. To maintain consistency, the company periodically randomly selects pi
> A large manufacturing company produces computer printers that are distributed and sold all over the United States. Due to lack of industry information, the company has a difficult time ascertaining its market share in different parts of the country. They
> Why do employees “blow the whistle” on other employees for unethical or illegal behavior? One study conducted by the AICPA reported the likelihood that employees would blow the whistle on another employee for such thin
> Information presented by GraphicSprings showed some of the highest and the lowest global rental rates per year per square foot of office space. Among the cities with the lowest rates were Houston, Riyadh, Melbourne, Amsterdam, and Bengaluru, with rental
> For the two large newspapers in your city, you are interested in knowing whether there is a significant difference in the average number of pages in each dedicated solely to advertising. You randomly select 10 editions of newspaper A and 6 editions of ne
> Use the information about each of the following samples to compute the confidence interval to estimate p. a) n = 44 and p^ = .51; compute a 90% confidence interval. b) n = 300 and p^ =.82; compute a 95% confidence interval. c) n = 1150 and p^ = .48; comp
> One of the thrusts of quality-control management is to examine the process by which a product is produced. This approach also applies to paperwork. In industries where large long-term projects are undertaken, days and even weeks may elapse as a change or
> A company’s auditor believes the per diem cost in Nashville, Tennessee, rose significantly between 2008 and 2019. To test this belief, the auditor samples 51 business trips from the company’s records for 2008; the sample average was $212 per day, with a
> Various types of retail outlets sell toys during the holiday season. Among them are specialty toy stores, large discount toy stores, and other retailers that carry toys as only one part of their stock of goods. Is there any difference in the dollar amoun
> Executives often spend so many hours in meetings that they have relatively little time to manage their individual areas of operation. What is the difference in mean time spent in meetings by executives of the aerospace industry and executives of the auto
> Is there a difference in the proportion of construction workers who are under 35 years of age and the proportion of telephone repair people who are under 35 years of age? Suppose a study is conducted in Calgary, Alberta, using random samples of 338 const
> A manufacturer uses two machines to drill holes in pieces of sheet metal used in engine construction. The workers who attach the sheet metal to the engine become inspectors in that they reject sheets so poorly drilled that they cannot be attached. The pr
> In manufacturing, does worker productivity drop on Friday? In an effort to determine whether it does, a company’s personnel analyst randomly selects from a manufacturing plant five workers who make the same part. He measures their outpu
> As the prices of heating oil and natural gas increase, consumers become more careful about heating their homes. Analysts want to know how warm homeowners keep their houses in January and how the results from Wisconsin and Tennessee compare. The analysts
> What is the average difference between the price of name-brand soup and the price of store-brand soup? To obtain an estimate, an analyst randomly samples eight stores. Each store sells its own brand and a national name brand. The prices of a can of name-
> Is there more variation in the output of one shift in a manufacturing plant than in another shift? In an effort to study this question, plant managers gathered productivity reports from the 8 A.M. to 4 P.M. shift for eight days. The reports indicated tha
> Cycle time in manufacturing can be viewed as the total time it takes to complete a product from the beginning of the production process. The concept of cycle time varies according to the industry and product or service being offered. Suppose a boat manuf
> A candy company fills a 20-ounce package of Halloween candy with individually wrapped pieces of candy. The number of pieces of candy per package varies because the package is sold by weight. The company wants to estimate the number of pieces per package.
> One of the most important aspects of a store’s image is the perceived quality of its merchandise. Other factors include merchandise pricing, assortment of products, convenience of location, and service. Suppose image perceptions of shoppers of specialty
> A tree nursery has been experimenting with fertilizer to increase the growth of seedlings. A sample of 35 two-year-old pine trees is grown for three more years with a cake of fertilizer buried in the soil near the trees’ roots. A second
> The Bureau of Labor Statistics shows that the average insurance cost to a company per hour worked for an employee by major industry group is $3.22 for construction workers and $3.97 for manufacturing workers. Suppose these figures were obtained from 14 c
> A national grocery store chain wants to test the difference in the average weight of turkeys sold in Detroit and the average weight of turkeys sold in Charlotte. According to the chain’s analyst, a random sample of 20 turkeys sold at the chain’s stores i
> A study was conducted to develop a scale to measure stress in the workplace. Respondents were asked to rate 26 distinct work events. Each event was to be compared with the stress of the first week on the job, which was awarded an arbitrary score of 500.
> There are several methods used by people to organize their lives in terms of keeping track of appointments, meetings, and deadlines. Some of these include using a desk calendar, using informal notes of scrap paper, keeping them “in your head,” using a da
> A study is conducted to estimate the average difference in bus ridership for a large city during the morning and afternoon rush hours. The transit authority’s analyst randomly selects nine buses because of the variety of routes they rep
> Suppose a large insurance company wants to estimate the difference between the average amount of term life insurance purchased per family and the average amount of whole life insurance purchased per family. To obtain an estimate, one of the companyâ
> Test the following hypotheses by using the given data. Let alpha = .05.
> How much experience do supply-chain transportation managers have in their field? Suppose in an effort to estimate this, 41 supply-chain transportation managers are surveyed and asked how many years of managerial experience they have in transportation. Su
> Use the following data to construct a 99% confidence interval to estimate p1 – p2.
> Test the following hypotheses by using the given data and alpha equal to .05. H0: p1 − p2 = 0 Ha: p1 − p2 ≠0
> Use the following data to construct a 99% confidence interval to estimate D. Assume the differences are normally distributed in the population.
> Suppose you own a plumbing repair business and employ 15 plumbers. You are interested in estimating the difference in the average number of calls completed per day between two of the plumbers. A random sample of 40 days of plumber A’s work results in a s
> The following data have been gathered from two related samples. The differences are assumed to be normally distributed in the population. Use these data and alpha of .01 to test the following hypotheses. H0: D = 0 Ha: D < 0 n = 21, d̅ =−1.16, sd = 1.01
> Construct a 95% confidence interval to estimate μ1 – μ2 by using the following data. Assume the populations are normally distributed.
> The following data come from independent samples drawn from normally distributed populations. Use these data to test the following hypotheses. Let the Type I error rate be .05. H0: μ1 − μ2 = 0 Ha: Î&fra
> Use the following data to construct a 98% confidence interval to estimate the difference between μ1 and μ2.
> Test the following hypotheses with the data given. Let α = .10. H0: μ1 − μ2 = 0 Ha: μ1 − μ2 ≠0
> According to the General Accounting Office of the U.S. government, the average age of a male federal worker is 43.6 years and that of a male worker in the nonfederal sector is 37.3 years. Is there any difference in the variation of ages of men in the fed
> Suppose a company from the United States does considerable business in the city of Johannesburg, South Africa, and wishes to establish a per diem rate for employee travel to that city. The company researcher is assigned this task, and in an effort to det
> One recent study showed that the average annual amount spent by an East Coast household on frankfurters was $23.84 compared with an average of $19.83 for West Coast households. Suppose a random sample of 11 East Coast households showed that the standard
> How long are resale houses on the market? One survey by the Houston Association of Realtors reported that in Houston, resale houses are on the market an average of 112 days. Of course, the length of time varies by market. Suppose random samples of 13 hou
> Suppose the data shown here are the results of a survey to investigate gasoline prices. Ten service stations were selected randomly in each of two cities and the figures represent the prices of a gallon of unleaded regular gasoline on a given day. Use th
> Test the following hypotheses by using the given sample information and α = .05. Assume the populations are normally distributed.
> The Trade Show Bureau conducted a survey to determine why people go to trade shows. The respondents were asked to rate a series of reasons on a scale from 1 to 5, with 1 representing little importance and 5 representing great importance. One of the reaso
> Test the following hypotheses by using the given sample information and α = .01. Assume the populations are normally distributed.
> Many Americans spend time worrying about paying their bills. A survey by Fleishman Hilliard Research for MassMutual discovered that 60% of Americans with kids say that paying bills is a major concern. This proportion compares to 52% of Americans without
> According to a CCH Unscheduled Absence survey, 9% of small businesses use telecommuting of workers in an effort to reduce unscheduled absenteeism. This proportion compares to 6% for all businesses. Is there really a significant difference between small b
> A large production facility uses two machines to produce a key part for its main product. Inspectors have expressed concern about the quality of the finished product. Quality-control investigation has revealed that the key part made by the two machines i
> Companies that recently developed new products were asked to rate which activities are most difficult to accomplish with new products. Options included such activities as assessing market potential, market testing, finalizing the design, developing a bus
> The marketing director of a large department store wants to estimate the average number of customers who enter the store every 5 minutes. She randomly selects 5-minute intervals and counts the number of arrivals at the store. She obtains the figures 58,
> Does age make a difference in the amount of savings a worker feels is needed to be secure at retirement? A study by CommSciences for Transamerica Asset Management found that .24 of workers in the 25–33 age category feel that $250,000 to $500,000 is enoug
> According to a study conducted by a major computer company, 59% of men and 70% of women say that weight is an extremely/very important factor in purchasing a laptop computer. Suppose this survey was conducted using 374 men and 481 women. Do these data sh
> In each of the following cases, calculate a confidence interval to estimate p1 − p2. a) n1 = 85, n2 = 90, p^1 = .75, p^2 = .67; level of confidence = 90% b) n1 = 1100, n2 = 1300, p^1 = .19, p^2 = .17; level of confidence = 95% c) n1 = 430, n2 = 399, x1 =
> Using the given sample information, test the following hypotheses. a) H0: p1 − p2 = 0 Ha: p1 − p2 ≠0 Note that x is the number in the sample having the characteristic of interest. b) H0: p1 â
> Is there a significant difference in the gasoline mileage of a car for regular unleaded and premium unleaded? To test this question, a business analyst randomly selected 15 drivers for a study. They were to drive their cars for one month on regular unlea
> Examine the following data. Assume the variances for the two populations are 22.74 and 26.65, respectively. a) Use the data to test the following hypotheses (( = .02). H0: μ1 − μ2 = 0 Ha: μ1 &ac
> A nationally known supermarket decided to promote its own brand of soft drinks on TV for two weeks. Before the ad campaign, the company randomly selected 21 of its stores across the United States to be part of a study to measure the campaign’s effectiven
> Lawrence and Glover published the results of a study in the Journal of Managerial Issues in which they examined the effects of accounting firm mergers on auditing delay. Auditing delay is the time between a company’s fiscal year-end and the date of the a
> Eleven employees were put under the care of the company nurse because of high cholesterol readings. The nurse lectured them on the dangers of this condition and put them on a new diet. Shown are the cholesterol readings of the 11 employees both before th
> The vice president of marketing brought to the attention of sales managers that most of the company’s manufacturer representatives contacted clients and maintained client relationships in a disorganized, haphazard way. The sales manager
> Some fast-food chains offer a lower-priced combination meal in an effort to attract budget-conscious customers. One chain test-marketed a burger, fries, and drink combination for $1.71. The weekly sales volume for these meals was impressive. Suppose the
> Because of uncertainty in real-estate markets, many homeowners are considering remodeling and constructing additions rather than selling. Probably the most expensive room in the house to remodel is the kitchen, with an average cost of about $23,400. In t
> Construct a 90% confidence interval to estimate D from the following sample information. Assume the differences are normally distributed in the population.
> Construct a 98% confidence interval to estimate D from the following sample information. Assume the differences are normally distributed in the population. d̅ = 40.56, sd = 26.58, n = 22
> Use the data given to test the following hypotheses (α = .05). Assume the differences are normally distributed in the population. H0: D = 0 Ha: D ≠0
> Use the data given and a 1% level of significance to test the following hypotheses. Assume the differences are normally distributed in the population. H0: D = 0 Ha: D > 0
> Some studies have shown that in the United States, men spend more than women buying gifts and cards on Valentine’s Day. Suppose an analyst wants to test this hypothesis by randomly sampling 9 men and 10 women with comparable demographic characteristics f
> Use the following sample information to construct a 90% confidence interval for the difference in the two population means.
> A study was made to compare the costs of supporting a family of four Americans for a year in different foreign cities. The lifestyle of living in the United States on an annual income of $75,000 was the standard against which living in foreign cities was
> What is the difference in average daily hotel room rates between Minneapolis and New Orleans? Suppose we want to estimate this difference by taking hotel rate samples from each city and using a 98% confidence level. The data for such a study follow. Use
> Based on an indication that mean daily car rental rates may be higher for Boston than for Dallas, a survey of eight car rental companies in Boston is taken and the sample mean car rental rate is $47, with a sample standard deviation of $3. Further, suppo
> A valve manufacturer produces a butterfly valve composed of two semicircular plates on a common spindle that is used to permit flow in one direction only. The semicircular plates are supplied by a vendor with specifications that the plates be 2.37 millim
> According to the National Association of Colleges and Employers, the average hourly wage of an undergraduate college student working as a co-op is $17.27 and the average hourly wage of a college student working as an intern is $16.57. Assume that such wa
> Suppose a realtor is interested in comparing the asking prices of midrange homes in Peoria, Illinois, and Evansville, Indiana. The realtor conducts a small telephone survey in the two cities, asking the prices of midrange homes. A random sample of 21 lis
