At Western University the historical mean of scholarship examination scores for freshman applications is 900. A historical population standard deviation σ = 180 is assumed known. Each year, the assistant dean uses a sample of applications to determine whether the mean examination score for the new freshman applications has changed. a. State the hypotheses. b. What is the 95% confidence interval estimate of the population mean examination score if a sample of 200 applications provided a sample mean x̅ = 935? c. Use the confidence interval to conduct a hypothesis test. Using α = .05, what is your conclusion? d. What is the p-value?
> A sample containing years to maturity and yield (%) CorporateBonds for 40 corporate bonds is contained in the file CorporateBonds (Barron’s). a. Develop a scatter diagram of the data using x = years to maturity as the independent variable. Does a simple
> For the holiday season of 2017, nearly 59 percent of consumers planned to buy gift cards. According to the National Retail Federation, millennials like to purchase gift cards (Dayton Daily News website). Consider the sample data in the file GiftCards. Th
> A portion of a data set containing information for 45 mutual funds that are part of the Morningstar Funds 500 follows. The complete data set is available in the file named MutualFunds. The data set includes the following five variables: Fund Type: The ty
> The Cincinnati Zoo and Botanical Gardens had a record attendance of 1.87 million visitors in 2017 (Cincinnati Business Courier website). Nonprofit organizations such as zoos and museums are becoming more sophisticated in their use of data to improve the
> Consider the following hypothesis test: H0: µ = 22 Ha: µ ≠ 22 A sample of 75 is used and the population standard deviation is 10. Compute the p-value and state your conclusion for each of the following sample results. Use α = .01. a. x̅ = 23 b. x̅ = 25.1
> The Tire Rack, America’s leading online distributor of tires and wheels, conducts extensive testing to provide customers with products that are right for their vehicle, driving style, and driving conditions. In addition, the Tire Rack m
> Recall that in exercise 50 the personnel director for Electronics Associates developed the following estimated regression equation relating an employee’s score on a job satisfaction test to length of service and wage rate. yÌ
> Recall that in exercise 49, the admissions officer for Clearwater College developed the following estimated regression equation relating final college GPA to the student’s SAT mathematics score and high-school GPA. ŷ = 21.
> A partial computer output from a regression analysis follows. a. Compute the missing entries in this output. b. Use the F test and α = .05 to see whether a significant relationship is present. c. Use the t test and α = .05 t
> The personnel director for Electronics Associates developed the following estimated regression equation relating an employee’s score on a job satisfaction test to his or her length of service and wage rate. ŷ= 14.4 - 8.69x1 + 13.5x2 where x1 = length of
> The admissions officer for Clearwater College developed the following estimated regression equation relating the final college GPA to the student’s SAT mathematics score and high-school GPA. ŷ = 21.41 + .0235x1 + .00486x2 where x1 = high-school grade po
> The Toyota Camry is one of the best-selling cars in North America. The cost of a previously owned Camry depends upon many factors, including the model year, mileage, and condition. To investigate the relationship between the car’s mileage and the sales p
> The Transactional Records Access Clearinghouse at Syracuse University reported data showing the odds of an Internal Revenue Service audit. The following table shows the average adjusted gross income reported and the percent of the returns that were audit
> Market betas for individual stocks are determined by simple linear regression. For each stock, the dependent variable is its quarterly percentage return (capital appreciation plus dividends) minus the percentage return that could be obtained from a risk-
> A marketing professor at Givens College is interested in the relationship between hours spent studying and total points earned in a course. Data collected on 10 students who took the course last quarter follow. Hours Spent Studying ……………………………. Total Po
> Consider the following hypothesis test: H0: µ ≤ 50 Ha: µ > 50 A sample of 60 is used and the population standard deviation is 8. Use the critical value approach to state your conclusion for each of the following sample results. Use α = .05. a. x̅ = 52.5
> The regional transit authority for a major metropolitan area wants to determine whether there is any relationship between the age of a bus and the annual maintenance cost. A sample of 10 buses resulted in the following data. Age of Bus (years) ………………… M
> A sociologist was hired by a large city hospital to investigate the relationship between the number of unauthorized days that employees are absent per year and the distance (miles) between home and work for the employees. A sample of 10 employees was cho
> In a manufacturing process the assembly line speed (feet per minute) was thought to affect the number of defective parts found during the inspection process. To test this theory, managers devised a situation in which the same batch of parts was inspected
> Jensen Tire & Auto is in the process of deciding whether to purchase a maintenance contract for its new computer wheel alignment and balancing machine. Managers feel that maintenance expense should be related to usage, and they collected the following in
> Is the number of square feet of living space a good predictor of a house’s selling price? The following data collected in April, 2015, show the square footage and selling price for fifteen houses in Winston Salem, North Carolina (Zillow.com). Size (1000
> The Dow Jones Industrial Average (DJIA) and the Standard & Poor’s 500 (S&P 500) indexes are used as measures of overall movement in the stock market. The DJIA is based on the price movements of 30 large companies; the S&P 50
> What is the purpose of testing whether β1 = 0? If we reject β2 = 0, does it imply a good fit?
> In your own words, explain the difference between an interval estimate of the mean value of y for a given x and an interval estimate for an individual value of y for a given x.
> Does a high value of r2 imply that two variables are causally related? Explain.
> Consider the following hypothesis test: H0: µ ≥ 80 Ha: µ < 80 A sample of 100 is used and the population standard deviation is 12. Compute the p-value and state your conclusion for each of the following sample results. Use α = .01. a. x̅ = 78.5 b. x̅ = 7
> A manufacturing company designed a factorial experiment to determine whether the number of defective parts produced by two machines differed and if the number of defective parts produced also depended on whether the raw material needed by each machine wa
> A factorial experiment was designed to test for any significant differences in the time needed to translate other languages into English with two computerized language translators. Because the type of language translated was also considered a significant
> A major manufacturer of golf equipment is considering three designs for a new driver: Design A, Design B, and Design C. Each design differs slightly in terms of the material used to construct the driver’s head and shaft. The company wou
> Jimmy Kimmel Live! on ABC, The Tonight Show Starring Jimmy Fallon on NBC, and The Late Show with Stephen Colbert on CBS are three popular late-night talk shows. The following table shows the number of viewers in millions for a 10-week period during the s
> A research firm tests the miles-per-gallon characteristics of three brands of gasoline. Because of different gasoline performance characteristics in different brands of automobiles, five brands of automobiles are selected and treated as blocks in the exp
> A Pew Research study conducted in 2017 found that approximately 75% of Americans believe that robots and computers might one day do many of the jobs currently done by people (Pew Research website, http://www.pewinternet.org/2017/10/04/americans-attitudes
> Three different assembly methods have been proposed for a new product. A completely randomized experimental design was chosen to determine which assembly method results in the greatest number of parts produced per hour, and 30 workers were randomly selec
> The following data show the percentage of 17- to 24-year-olds who are attending college in several metropolitan statistical areas in four geographic regions of the United States (U.S. Census Bureau website, https://www .census.gov/data.html). // Use α
> The U.S. Environmental Protection Agency (EPA) monitors levels of pollutants in the air for cities across the country. Ozone pollution levels are measured using a 500-point scale; lower scores indicate little health risk, and higher scores indicate great
> A study reported in the Journal of Small Business Management concluded that self-employed individuals do not experience higher job satisfaction than individuals who are not self-employed. In this study, job satisfaction is measured using 18 items, each o
> Consider the following hypothesis test: H0: µ = 15 Ha: µ ≠ 15 A sample of 50 provided a sample mean of 14.15. The population standard deviation is 3. a. Compute the value of the test statistic. b. What is the p-value? c. At α = .05, what is your conclusi
> In a completely randomized experimental design, three brands of paper towels were tested for their ability to absorb water. Equal-size towels were used, with four sections of towels tested per brand. The absorbency rating data follow. At a .05 level of s
> The Harris Poll tracks the favorite sport of Americans who follow at least one sport. Results of the poll show that professional football is the favorite sport of 33% of Americans who follow at least one sport, followed by baseball at 15%, menâ
> A Financial Times/Harris Poll surveyed people in six countries to assess attitudes toward a variety of alternate forms of energy. The data in the following table are a portion of the poll’s findings concerning whether people favor or op
> An ambulance service responds to emergency calls for two counties in Virginia. One county is an urban county and the other is a rural county. A sample of 471 ambulance calls over the past two years showed the county and the day of the week for each emerg
> The Barna Group conducted a survey about church attendance. The survey respondents were asked about their church attendance and asked to indicate their age. Use the sample data to determine whether church attendance is independent of age. Using a .05 lev
> A Pew Research Center survey asked respondents if they would rather live in a place with a slower pace of life or a place with a faster pace of life. The survey also asked the respondent’s gender. Consider the following sample data. a
> As listed by The Art Newspaper Visitor Figures Survey (https://www.theartnewspaper.com/visitor-figures-2017), the five most-visited art museums in the world are the Louvre Museum, the National Museum in China, the Metropolitan Museum of Art, the Vatican
> Arconic Inc. is a producer of aluminum components for the avionics and automotive industries. At its Davenport Works plant, an engineer has conducted a quality-control test in which aluminum coils produced in all three shifts were inspected. The study wa
> Data from the Office for National Statistics show that the mean age at which men in Great Britain married in 2013 is 30.8 years. A news reporter noted that this represents a continuation of the trend of waiting until a later age to wed. A new sample of 4
> Michigan State University’s Collegiate Employment Research Institute found that starting salary for recipients of bachelor's degrees in business was $50,032 in 2017. The results for a sample of 100 business majors receiving a bachelor’s degree in 2018 sh
> Consider the following hypothesis test: H0: µ ≤ 25 Ha: µ > 25 A sample of 40 provided a sample mean of 26.4. The population standard deviation is 6. a. Compute the value of the test statistic. b. What is the p-value? c. At α = .01, what is your conclusio
> CNN reports that young children in the United States are exposed to an average of 4 hours of background television per day. Having the television on in the background while children are doing other activities may have adverse consequences on a child’s we
> A production line operates with a mean filling weight of 16 ounces per container. Overfilling or underfilling presents a serious problem and when detected requires the operator to shut down the production line to readjust the filling mechanism. From past
> According to the U.S. Transportation Security Administration (TSA), 2% of the 771,556,886 travelers who utilized 440 federalized airports in 2017 waited more than 20 minutes in the TSA security line. The file TSAWaitTimes contains waiting times in TSA se
> NDC Technology’s MM710e On-Line Snacks Gauge rapidly measures surface brownness of potato chips just before packaging. This allows for a high degree of control over this important characteristic of a potato chip; chips that are too brown are overfried, a
> According to Ericsson’s 2016 ConsumerLab TV & Media report, the average person in the United States spends 23 minutes per day channel surfing. The file ChannelSurfing provides the number of minutes per day looking for something to watch on television for
> H0: µ = 120 and Ha: µ ≠ 120 are used to test whether a bath soap production process is meeting the standard output of 120 bars per batch. Use a .05 level of significance for the test and a planning value of 5 for the standard deviation. a. If the mean ou
> A federal funding program is available to low-income neighborhoods. To qualify for the funding, a neighborhood must have a mean household income of less than $15,000 per year. Neighborhoods with mean annual household income of $15,000 or more do not qual
> Shorney Construction Company bids on projects assuming that the mean idle time per worker is 72 or fewer minutes per day. A sample of 30 construction workers will be used to test this assumption. Assume that the population standard deviation is 20 minute
> Vegetarians are much less common in the United States than in the rest of the world. In a 2018 survey of 11,000 people in the United States, VeganBits found 55 who are vegetarians. a. Develop a point estimate of the proportion of people in the United Sta
> The manager of the Danvers-Hilton Resort Hotel stated that the mean guest bill for a weekend is $600 or less. A member of the hotel’s accounting staff noticed that the total charges for guest bills have been increasing in recent months.
> A radio station in Myrtle Beach announced that at least 90% of the hotels and motels would be full for the Memorial Day weekend. The station advised listeners to make reservations in advance if they planned to be in the resort over the weekend. On Saturd
> According to Inc.com, 79% of job seekers used social media in their job search in 2018. Many believe this number is inflated by the proportion of 22- to 30-year-old job seekers who use social media in their job search. A survey of 22- to 30-year-old job
> Members of the millennial generation are continuing to be dependent on their parents (either living with or otherwise receiving support from parents) into early adulthood. A family research organization has claimed that, in past generations, no more than
> An airline promotion to business travelers is based on the assumption that two-thirds of business travelers use a laptop computer on overnight business trips. a. State the hypotheses that can be used to test the assumption. b. What is the sample proporti
> According to Expedia, 52% of Americans report that they generally can sleep during flights. Are people who fly frequently more likely to be able to sleep during flights? Suppose we have a random sample of 510 individuals who flew at least 25,000 miles la
> According to the the National Association of Realtors, it took an average of three weeks to sell a home in 2017. Data for the sale of 40 randomly selected homes sold in Greene County, Ohio, in 2017 showed a sample mean of 3.6 weeks with a sample standard
> The chamber of commerce of a Florida Gulf Coast community advertises that area residential property is available at a mean cost of $125,000 or less per lot. Suppose a sample of 32 properties provided a sample mean of $130,000 per lot and a sample standar
> SmartAsset reports that the average weekly earnings for workers who have not received a high school diploma is $493 in 2018. Suppose you would like to determine if the average weekly earnings for workers who have received a high school diploma is signifi
> The Infrastructure Report Card (IRC) reports that of 614,387 U.S. bridges, 9.1% were structurally deficient as of last year. The IRC also reports that more than 1300 California bridges fall under this category. How does California compare to the nation?
> In 2017, 42.54% of the nearly 2.7 million reports taken nationwide by the Federal Trade Commission’s Consumer Sentinel Network dealt with instances of fraud. Consider results of a random sample of 42,296 of the reports taken by the Consumer Sentinel Netw
> According to CNN, 55% of all U.S. smartphone users have used their GPS capability to get directions. Suppose a major provider of wireless telephone service in Canada wants to know how GPS usage by its customers compares with U.S. smartphone users. The co
> A recent survey from PayScale found that 46% of U.S. workers— roughly 22 million—are underemployed, either working part-time or at jobs that don’t allow them to use their education or skills. Suppose that the numbers of hours worked in the past week were
> Huston Systems Private Limited reports that smart traffic signals and signs can measure a passing vehicle’s speed. Consider the speeds of 15,717 vehicles collected as they passed 35 MPH speed limit signs throughout the United States in 2018 that are prov
> Although airline schedules and cost are important factors for business travelers when choosing an airline carrier, a USA Today survey found that business travelers list an airline’s frequent flyer program as the most important factor. From a sample of n
> Credit card ownership varies across age groups. In 2018, CreditCards.com estimated that the percentage of people who own at least one credit card is 67% in the 18–24 age group, 83% in the 25–34 age group, 76% in the 35–49 age group, and 78% in the 50+ ag
> A well-known bank credit card firm wishes to estimate the proportion of credit card holders who carry a nonzero balance at the end of the month and incur an interest charge. Assume that the desired margin of error is .03 at 98% confidence. a. How large a
> In 2014, the Centers for Disease Control reported the percentage of people 18 years of age and older who smoke. Suppose that a study designed to collect new data on smokers and nonsmokers uses a preliminary estimate of the proportion who smoke of .30. a.
> A survey of 750 likely voters in Ohio was conducted by the Rasmussen Poll just prior to the general election. The state of the economy was thought to be an important determinant of how people would vote. Among other things, the survey found that 165 of t
> The Pew Research Center has conducted extensive research on social media usage. One finding, reported in June 2018, was that 78% of adults aged 18 to 24 use Snapchat. Another finding was that 45% of those aged 18 to 24 use Twitter. Assume the sample size
> A USA Today/CNN/Gallup survey of 369 working parents found 200 who said they spend too little time with their children because of work commitments. a. What is the point estimate of the proportion of the population of working parents who feel they spend t
> The National Center for Education Statistics reported that 47% of college students work to pay for tuition and living expenses. Assume that a sample of 450 college students was used in the study. a. Provide a 95% confidence interval for the population pr
> The American Potato Growers Association (APGA) would like to test the claim that the proportion of fast-food orders this year that include French fries exceeds the proportion of fast-food orders that included French fries last year. Suppose that a random
> Annual salary plus bonus data for chief executive officers are presented in the BusinessWeek Annual Pay Survey. A preliminary sample showed that the standard deviation is $675 with data provided in thousands of dollars. How many chief executive officers
> In developing patient appointment schedules, a medical center wants to estimate the mean time that a staff member spends with each patient. How large a sample should be taken if the desired margin of error is two minutes at a 95% level of confidence? How
> Mileage tests are conducted for a particular model of automobile. If a 98% confidence interval with a margin of error of 1 mile per gallon is desired, how many automobiles should be used in the test? Assume that preliminary mileage tests indicate the sta
> Obesity is a risk factor for many health problems such as type 2 diabetes, high blood pressure, joint problems, and gallstones. Using data collected in 2018 through the National Health and Nutrition Examination Survey, the National Institute of Diabetes
> The Health Care Cost Institute tracks health care expenditures for beneficiaries under the age of 65 who are covered by employer-sponsored private health insurance. The data contained in the file DrugCost are consistent with the institute’s findings conc
> The Centers for Disease Control and Prevention (CDC) define a healthy sleep duration to be at least seven hours per day. The CDC reports that the percentage of people who report a healthy sleep duration varies by marital status. The CDC also reports that
> The 92 million Americans of age 50 and over control 50 percent of all discretionary income. AARP estimates that the average annual expenditure on restaurants and carryout food was $1873 for individuals in this age group. Suppose this estimate is based on
> A survey conducted by the American Automobile Association showed that a family of four spends an average of $215.60 per day while on vacation. Suppose a sample of 64 families of four vacationing at Niagara Falls resulted in a sample mean of $252.45 per d
> A sample survey of 54 discount brokers showed that the mean price charged for a trade of 100 shares at $50 per share was $33.77. The survey is conducted annually. With the historical data available, assume a known population standard deviation of $15. a.
> In a 2018 study, Phoenix Marketing International identified Bridgeport, Connecticut; San Jose, California; Washington, D.C.; and Lexington Park, Maryland as the four U.S. cities with the highest percentage of millionaires (Kiplinger website, https://www.
> CEOs who belong to a popular business-oriented social networking service have an average of 930 connections. Do other members have fewer connections than CEOs? The number of connections for a random sample of 7,515 members who are not CEOs is provided in
> A sample containing years to maturity and yield for 40 corporate bonds are contained in the file CorporateBonds. a. What is the sample mean years to maturity for corporate bonds and what is the sample standard deviation? b. Develop a 95% confidence inter
> The American Press Institute reports that almost 70% of all American adults use a computer to gain access to news. Based on generational differences, you suspect that the proportion of American adults under 30 years old who use a computer to gain access
> Each year, more than 2 million people in the United States become infected with bacteria that are resistant to antibiotics. In particular, the Centers of Disease Control and Prevention have launched studies of drug-resistant gonorrhea (CDC.gov). Of 142 c
> A large automobile insurance company selected samples of single and married male policyholders And recorded the number who made an insurance claim over the preceding three-year period. Single Policyholders …………………………….. Married Policyholders n1 = 400 ……
> Country Financial, a financial services company, uses surveys of adults age 18 and older to determine if personal financial fitness is changing over time. A recent sample of 1000 adults showed 410 indicating that their financial security was more than fa
> In Born Together—Reared Apart: The Landmark Minnesota Twin Study (http://www.hup.harvard.edu/catalog.php?isbn=9780674055469), Nancy Segal discusses the efforts of research psychologists at the University of Minnesota to understand simil
> The National Association of Home Builders provided data on the cost of the most popular home remodeling projects. Sample data on cost in thousands of dollars for two types of remodeling projects are as follows. a. Develop a point estimate of the differ
> Mutual funds are classified as load or no-load funds. Load funds require an investor to pay an initial fee based on a percentage of the amount invested in the fund. The no-load funds do not require this initial fee. Some financial advisors argue that the
> Statista reports that the average monthly lease payment for an automobile is falling in the United States (Statista.com), but does this apply to all classes of automobiles? Suppose you are interested in whether this trend is true for sport utility vehicl
