Investors commonly use the standard deviation of the monthly percentage return for a mutual fund as a measure of the risk for the fund; in such cases, a fund that has a larger standard deviation is considered more risky than a fund with a lower standard deviation. The standard deviation for the American Century Equity Growth fund and the standard deviation for the Fidelity Growth Discovery fund were recently reported to be 15.0% and 18.9%, respectively. Assume that each of these standard deviations is based on a sample of 60 months of returns. Do the sample results support the conclusion that the Fidelity fund has a larger population variance than the American Century fund? Which fund is more risky?
> The following data are from a completely randomized design. In the following calculations, use α = .05. / a. Use analysis of variance to test for a significant difference among the means of the three treatments. b. Use Fisher’s LSD procedure to determi
> The following data are from a completely randomized design. a. At the α = .05 level of significance, can we reject the null hypothesis that the means of the three treatments are equal? b. Use Fisher’s LSD procedure to te
> The Consumer Reports Restaurant Customer Satisfaction Survey is based upon 148,599 visits to full-service restaurant chains (Consumer Reports website, https://www.consumerreports.org/cro/restaurants/buying-guide/index.htm). One of the variables in the st
> How long it takes paint to dry can have an impact on the production capacity of a business. In May 2018, Deal’s Auto Body & Paint in Prescott, Arizona, invested in a paint-drying robot to speed up its process (The Daily Courier webs
> Auditors must make judgments about various aspects of an audit on the basis of their own direct experience, indirect experience, or a combination of the two. In a study, auditors were asked to make judgments about the frequency of errors to be found in a
> The following data are from a completely randomized design. a. Compute the sum of squares between treatments. b. Compute the mean square between treatments. c. Compute the sum of squares due to error. d. Compute the mean square due to error. e. Set up
> The following table contains observed frequencies for a sample of 200. Test for independence of the row and column variables using α = .05.
> The Ertl Company is well known for its high-quality die-cast metal alloy toy replicas of tractors and other farm equipment. As part of a periodic procurement evaluation, Ertl is considering purchasing parts for a toy tractor line from three different sup
> Social media is becoming more and more popular around the world. Statista.com provides estimates of the number of social media users in various countries in 2017 as well as the projections for 2022. Assume that the results for surveys in the United Kingd
> A tax preparation firm is interested in comparing the quality of work at two of its regional offices. The observed frequencies showing the number of sampled returns with errors and the number of sampled returns that were correct are as follows. a. What
> Customers arrive at a movie theater at the advertised movie time only to find that they have to sit through several previews and prepreview ads before the movie starts. Many complain that the time devoted to previews is too long. A preliminary sample con
> The Carnegie Classification of Institutes of Higher Education categorizes colleges and universities on the basis of their research and degree-granting activities. Universities that grant doctoral degrees are placed into one of three classifications: mode
> Benson Manufacturing is considering ordering electronic components from three different suppliers. The suppliers may differ in terms of quality in that the proportion or percentage of defective components may differ among the suppliers. To evaluate the p
> The sample data below represent the number of late and on time flights for Delta, United, and US Airways. Airline a. Formulate the hypotheses for a test that will determine if the population proportion of late flights is the same for all three airlines
> The manager at a Whole Foods Market is responsible for managing store inventory. The mathematical models that she uses to determine how much inventory to stock rely on product demand being normally distributed. In particular, the weekly demand of srirach
> Bob Feller, an Iowa farmer, has recorded the daily high temperatures during the same five-day stretch in May over the past five years. Bob is interested in whether this data suggests that the daily high temperature obeys a normal distribution. Use Î
> The National Highway Traffic Safety Administration reported the percentage of traffic accidents occurring each day of the week. Assume that a sample of 420 accidents provided the following data. a. Conduct a hypothesis test to determine if the proportio
> The Wall Street Journal’s Shareholder Scoreboard tracks the performance of 1000 major U.S. companies. The performance of each company is rated based on the annual total return, including stock price changes and the reinvestment of divid
> Mars, Inc. manufactures M&€™s, one of the most popular candy treats in the world. The milk chocolate candies come in a variety of colors including blue, brown, green, orange, red, and yellow. The overall proportions for the colors are .24 b
> During the first 13 weeks of the television season, the Saturday evening 8 p.m. to 9 p.m. audience proportions were recorded as ABC 29%, CBS 28%, NBC 25%, and independents 18%. A sample of 300 homes two weeks after a Saturday night schedule revision yiel
> The following data are believed to have come from a normal distribution. Use the goodness of fit test and α = .05 to test this claim.
> Many medical professionals believe that eating too much red meat increases the risk of heart disease and cancer. Suppose you would like to conduct a survey to determine the yearly consumption of beef by a typical American and want to use 3 pounds as the
> Reconsider the observed frequencies in exercise 1 a. Compute the sample proportion for each population. b. Use the multiple comparison procedure to determine which population proportions differ significantly. Use a .05 level of significance. Exercise 1:
> Test the following hypotheses by using the χ2 goodness of fit test. H0: pA = .40, pB = .40, and pC = .20 Ha: The population proportions are not pA = .40, pB = .40, and pC = .20 A sample of size 200 yielded 60 in category A, 120 in category B, and 20 in c
> On a television program, two movie critics provide their reviews of recent movies and discuss. It is suspected that these hosts deliberately disagree in order to make the program more interesting for viewers. Each movie review is categorized as Pro (&aci
> The National Sleep Foundation used a survey to determine whether hours of sleep per night are independent of age. A sample of individuals was asked to indicate the number of hours of sleep per night with categorical options: fewer than 6 hours, 6 to 6.9
> The race for the 2013 Academy Award for Actress in a Leading Role was extremely tight, featuring several worthy performances. The nominees were Jessica Chastain for Zero Dark Thirty, Jennifer Lawrence for Silver Linings Playbook, Emmanuelle Riva for Amou
> The Wall Street Journal Annual Corporate Perceptions Study surveyed readers and asked how they rated the quality of management and the reputation of the company for more than 250 worldwide corporations. Both the quality of management and the reputation o
> A J. D. Power and Associates vehicle quality survey asked new owners a variety of questions about their recently purchased automobile. One question asked for the owner’s rating of the vehicle using categorical responses of average, outs
> A Deloitte employment survey asked a sample of human resource executives how their company planned to change its workforce over the next 12 months. A categorical response variable showed three options: The company plans to hire and add to the number of e
> A Bloomberg Businessweek subscriber study asked, “In the past 12 months, when traveling for business, what type of airline ticket did you purchase most often?” A second question asked if the type of airline ticket purc
> Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $45,000 and $60,000. Assume that a 95% confidence interval estimate of the population mean annual starting salary is desired. What
> The following table contains observed frequencies for a sample of 240. Test for independence of the row and column variables using α = .05.
> Use the sample data below to test the hypotheses H0: p1 = p2 = p3 Ha: Not all population proportions are equal where pi is the population proportion of Yes responses for population i. Using a .05 level of significance, what is the p-value and what is you
> The competitive advantage of small American factories such as Tolerance Contract Manufacturing lies in their ability to produce parts with highly narrow requirements, or tolerances, that are typical in the aerospace industry. Consider a product with spec
> Consider a day when the Dow Jones Industrial Average went up 149.82 points. The following table shows the stock price changes for a sample of 12 companies on that day. a. Compute the sample variance for the daily price change. b. Compute the sample sta
> In 2017, Americans spent a record-high $9.1 billion on Halloween- related purchases (the balance website, https://www.thebalance.com /halloween-spending-statistics-facts-and-trends-3305716). Sample data showing the amount, in dollars, 16 adults spent on
> To analyze the risk, or volatility, associated with investing in General Electric common stock, consider a sample of the eight quarterly percent total returns. The percent total return includes the stock price change plus the dividend payment for the qua
> In 2018, Mike Krzyewski and John Calipari topped the list of highest-paid college basketball coaches (Sports Illustrated website, https://www.si.com/college-basketball/2018/03/01/highest-paid-college-basketball -coaches-salaries-mike-krzyewski-john-calip
> Amazon.com is testing the use of drones to deliver packages for same-day delivery. In order to quote narrow time windows, the variability in delivery times must be sufficiently small. Consider a sample of 24 drone deliveries with a sample variance of s2
> A sample of 16 items provides a sample standard deviation of 9.5. Test the following hypotheses using α = .05. What is your conclusion? Use both the p-value approach and the critical value approach.
> A research hypothesis is that the variance of stopping distances of automobiles on wet pavement is substantially greater than the variance of stopping distances of automobiles on dry pavement. In the research study, 16 automobiles traveling at the same s
> The U.S. Energy Information Administration (US EIA) reported that the average price for a gallon of regular gasoline is $2.94. The US EIA updates its estimates of average gas prices on a weekly basis. Assume the standard deviation is $.25 for the price o
> Battery life is an important issue for many smartphone owners. Public health studies have examined “low-battery anxiety” and acute anxiety called nomophobia that results when a smartphone user’s phone
> On the basis of data provided by a Romac salary survey, the variance in annual salaries for senior partners in public accounting firms is approximately 2.1 and the variance in annual salaries for managers in public accounting firms is approximately 11.1.
> A sample of 20 items provides a sample standard deviation of 5. a. Compute the 90% confidence interval estimate of the population variance. b. Compute the 95% confidence interval estimate of the population variance. c. Compute the 95% confidence interva
> The variance in a production process is an important measure of the quality of the process. A large variance often signals an opportunity for improvement in the process by finding ways to reduce the process variance. Jelly Belly Candy Company is testing
> Barron’s has collected data on the top 1000 financial advisers. Merrill Lynch and Morgan Stanley have many of their advisers on this list. A sample of 16 of the Merrill Lynch advisers and 10 of the Morgan Stanley advisers showed that the advisers managed
> In its 2016 Auto Reliability Survey, Consumer Reports asked subscribers to report their maintenance and repair costs. Most individuals are aware of the fact that the average annual repair cost for an automobile depends on the age of the automobile. A res
> Consider the following hypothesis test. H0: σ21 = σ22 Ha: σ21 ≠ σ22 a. What is your conclusion if n1 = 21, s21= 8.2, n2 = 26, and s22 = 4.0? Use α = .05 and the p-value approach. b. Repeat the test using the critical value approach.
> A sample of 16 items from population 1 has a sample variance s12 = 5.8 and a sample of 21 items from population 2 has a sample variance s22 = 2.4. Test the following hypotheses at the .05 level of significance. a. What is your conclusion using the p-va
> Find the following F distribution values from Table 4 of Appendix B. a. F.05 with degrees of freedom 5 and 10 b. F.025 with degrees of freedom 20 and 15 c. F.01 with degrees of freedom 8 and 12 d. F.10 with degrees of freedom 10 and 20
> Refer to the Scheer Industries example in Section 8.2. Use 6.84 days as a planning value for the population standard deviation. a. Assuming 95% confidence, what sample size would be required to obtain a margin of error of 1.5 days? b. If the precision st
> Magazine Subscribers. A Fortune study found that the variance in the number of vehicles owned or leased by subscribers to Fortune magazine is .94. Assume a sample of 12 subscribers to another magazine provided the following data on the number of vehicles
> In 2016, the Graduate Management Admission Council reported that the variance in GMAT scores was 14,660. At a recent summit, a group of economics professors met to discuss the GMAT performance of undergraduate students majoring in economics. Some expecte
> Consumer Reports uses a 100-point customer satisfaction score to rate the nation’s major chain stores. Assume that from past experience with the satisfaction rating score, a population standard deviation of σ = 12 is expected
> Find the following chi-square distribution values from Table 11.1 or Table 3 of Appendix B. a. χ2.05 with df = 5 b. χ2.025 with df = 15 c. χ2.975 with df = 20 d. χ2.01 with df = 10 e. χ2.95 with df = 18
> The following results are for independent random samples taken from two populations. Sample 1 ……………………………………. Sample 2 n1 = 20 …………………………………………. n2 = 30 x̅1 = 22.5 …………………………………….. x̅2 = 20.1 σ1 = 2.5 ……………………………………….. σ2 = 4.8 a. What is the point est
> Will improving customer service result in higher stock prices for the companies providing the better service? “When a company’s satisfaction score has improved over the prior year’s results and is abo
> Consumer Reports uses a survey of readers to obtain customer satisfaction ratings for the nation’s largest supermarkets (Consumer Reports, https://www.consumerreports.org/products/grocery-stores-supermarkets/ratings-overview/). Each survey respondent is
> Suppose that you are responsible for making arrangements for a business convention and that you have been charged with choosing a city for the convention that has the least expensive hotel rooms. You have narrowed your choices to Atlanta and Houston. The
> USA Today reports that the average expenditure on Valentine’s Day is $100.89. Do male and female consumers differ in the amounts they spend? The average expenditure in a sample survey of 40 male consumers was $135.67, and the average expenditure in a sam
> Condé Nast Traveler conducts an annual survey in which readers rate their favorite cruise ship. All ships are rated on a 100-point scale, with higher values indicating better service. A sample of 37 ships that carry fewer than 500 passengers resulted in
> The range for a set of data is estimated to be 36. a. What is the planning value for the population standard deviation? b. At 95% confidence, how large a sample would provide a margin of error of 3? c. At 95% confidence, how large a sample would provide
> Carl Allen and Norm Nixon are two loan officers at Brea Federal Savings and Loan Bank. The bank manager is interested in comparing the default rate on the loans approved by Carl to the default rate on the loans approved by Norm. In the sample of loans co
> The Adecco Workplace Insights Survey sampled men and women workers and asked if they expected to get a raise or promotion this year. Suppose the survey sampled 200 men and 200 women. If 104 of the men replied Yes and 74 of the women replied Yes, are the
> Tourism is extremely important to the economy of Florida. Hotel occupancy is an often-reported measure of visitor volume and visitor activity (Orlando Sentinel, https://www.orlandosentinel.com/business/tourism/os-bz-hotel -occupancy-dip-20180522-story.ht
> Oil wells are expensive to drill, and dry wells are a great concern to oil exploration companies. The domestic oil and natural gas producer Aegis Oil, LLC describes on its website how improvements in technologies such as three-dimensional seismic imaging
> Minnesota had the highest turnout rate of any state for the 2016 presidential election (United States Election Project website). Political analysts wonder if turnout in rural Minnesota was higher than turnout in the urban areas of the state. A sample sho
> Researchers with Oceana, a group dedicated to preserving the ocean ecosystem, reported finding that 33% of fish sold in retail outlets, grocery stores, and sushi bars throughout the United States had been mislabeled (San Francisco Chronicle, https://www.
> Forbes reports that women trust recommendations from Pinterest more than recommendations from any other social network platfor (https://www.forbes.com/sites/marketshare/2012/03/20/why-brand-managers-need-to-take-an-interest-in-pinterest/#5e3b22fb6375). B
> A Businessweek/Harris poll asked senior executives at large corporations their opinions about the economic outlook for the future. One question was, “Do you think that there will be an increase in the number of full-time employees at your company over th
> Consider the following hypothesis test. H0: µ1 - µ2 = 0 Ha: µ1 - µ2 ≠ 0 The following results are for two independent samples taken from the two populations. Sample 1 …………………………………….. Sample 2 n1 = 80 ………………………………………….. n2 = 70 x̅1 = 104 ………………………………………
> Consider the hypothesis test H0: p1 - p2 ≤ 0 Ha: p1 - p2 > 0 The following results are for independent samples taken from the two populations. Sample 1 …………………………… Sample 2 n1 = 200 …………………………….. n2 = 300 p̅1 = .22 ……………………………….. p̅ 2 = .16 a. What is
> How large a sample should be selected to provide a 95% confidence interval with a margin of error of 10? Assume that the population standard deviation is 40. Applications
> Consider the following results for independent samples taken from two populations. Sample 1 …………………………………….. Sample 2 n1 = 400 ……………………………………. n2 = 300 p̅1 = .48 ……………………………………… p̅2 = .36 a. What is the point estimate of the difference between the two
> A personal fitness company produces both a deluxe and a standard model of a smoothie blender for home use. Selling prices obtained from a sample of retail outlets follow. a. The manufacturer’s suggested retail prices for the two model
> Scores in the first and fourth (final) rounds for a sample of 20 golfers who competed in PGA tournaments are shown in the following table. Suppose you would like to determine if the mean score for the first round of a PGA Tour event is significantly diff
> The College Board SAT college entrance exam consists of three parts: math, writing, and critical reading. Sample data showing the math and writing scores for a sample of 12 students who took the SAT follow. a. Use a .05 level of significance and test f
> The Global Business Travel Association reported the domestic airfare for business travel for the current year and the previous year. Below is a sample of 12 flights with their domestic airfares shown for both years. a. Formulate the hypotheses and test
> Bank of America’s Consumer Spending Survey collected data on annual credit card charges in seven different categories of expenditures: transportation, groceries, dining out, household expenses, home furnishings, apparel, and entertainment. Using data fro
> The price per share of stock for a sample of 25 companies was recorded at the beginning of the first financial quarter and then again at the end of the first financial quarter. How stocks perform during the first financial quarter is an indicator of what
> A market research firm used a sample of individuals to rate the purchase potential of a particular product before and after the individuals saw a new television commercial about the product. The purchase potential ratings were based on a 0 to 10 scale, w
> The following data are from matched samples taken from two populations. a. Compute the difference value for each element. b. Compute dÌ…. c. Compute the standard deviation sd. d. What is the point estimate of the difference between the two
> Consider the following hypothesis test. H0: µ1 - µ2 ≤ 0 Ha: µ1 - µ2 > 0 The following results are for two independent samples taken from the two populations. Sample 1 ………………………………... Sample 2 n1 = 40 …………………………………….. n2 = 50 x̅1 = 25.2 …………………………………. x̅
> Marvel Studio’s motion picture Guardians of the Galaxy opened over the first two days of the 2014 Labor Day weekend to a then record-breaking $94.3 million in ticket sales revenue in North America. The ticket sales revenue in dollars for a sample of 30 t
> Consider the following hypothesis test. H0: µd ≤ 0 Ha: µd > 0 The following data are from matched samples taken from two populations. a. Compute the difference value for each element. b. Compute dÌ
> The success of an airline depends heavily on its ability to provide a pleasant customer experience. One dimension of customer service on which airlines compete is on-time arrival. The file LateFlights contains a sample of data from delayed flights showin
> Periodically, Merrill Lynch customers are asked to evaluate Merrill Lynch financial consultants and services. Higher ratings on the client satisfaction survey indicate better service, with 7 the maximum service rating. Independent samples of service rati
> The College Board provided comparisons of Scholastic Aptitude Test (SAT) scores based on the highest level of education attained by the test taker’s parents. A research hypothesis was that students whose parents had attained a higher le
> Hotel room pricing changes over time (Lodging Magazine), but is there a difference between Europe hotel prices and U.S. hotel prices? The file IntHotels contains changes in the hotel prices for 47 major European cities and 53 major U.S. cities. a. On the
> The Tippie College of Business obtained the following results on the salaries of a recent graduating class: Finance Majors ……………………………………… Business Analytics Majors n1 = 110 …………………………………………………………………………… n2 = 30 x̅1 = $48,537 …………………………………………………………….. x
> The increasing annual cost (including tuition, room, board, books, and fees) to attend college has been widely discussed (http://time.com/money/4543839/college-costs-record-2016/). The following random samples show the annual cost of attending private an
> The U.S. Department of Transportation provides the number of miles that residents of the 75 largest metropolitan areas travel per day in a car. Suppose that for a simple random sample of 50 Buffalo residents the mean is 22.5 miles a day and the standard
> Consider the following data for two independent random samples taken from two normal populations. a. Compute the two sample means. b. Compute the two sample standard deviations. c. What is the point estimate of the difference between the two population
> Consider the following hypothesis test. H0: µ1 - µ2 = 0 Ha: µ1 - µ2 ≠ 0 The following results are from independent samples taken from two populations. Sample 1 ……………………………… Sample 2 n1 = 35 ………………………………….. n2 = 40 x̅1 = 13.6 ……………………………… x̅2 = 10.1 σ1 =
> Health insurers are beginning to offer telemedicine services online that replace the common office visit. Wellpoint provides a video service that allows subscribers to connect with a physician online and receive prescribed treatments (Bloomberg Businessw
> Find the t value(s) for each of the following cases. a. Upper tail area of .025 with 12 degrees of freedom b. Lower tail area of .05 with 50 degrees of freedom c. Upper tail area of .01 with 30 degrees of freedom d. Where 90% of the area falls between th
> In a study conducted by Zogby International for the Democrat and Chronicle, more than 700 New Yorkers were polled to determine whether the New York state government works. Respondents surveyed were asked questions involving pay cuts for state legislators
> Meticulous Drill & Reamer (MD&R) specializes in drilling and boring precise holes in hard metals (e.g., steel alloys, tungsten carbide, and titanium). The company recently contracted to drill holes with 3-centimeter diameters in large carbon-stee
