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 fair. Just a year before, a sample of 900 adults showed 315 indicating that their financial security was more than fair. a. State the hypotheses that can be used to test for a significant difference between the population proportions for the two years. b. Conduct the hypothesis test and compute the p-value. At a .05 level of significance, what is your conclusion? c. What is the 95% confidence interval estimate of the difference between the two population proportions? What is your conclusion?
> 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
> 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 wh
> 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 ……
> 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
> Safegate Foods, Inc., is redesigning the checkout lanes in its supermarkets throughout the country and is considering two designs. Tests on customer checkout times conducted at two stores where the two new systems have been installed result in the follow
> A salesperson makes four calls per day. A sample of 100 days gives the following frequencies of sales volumes. Number of Sales ………………
> The Federal Government wants to determine if the mean number of business emails sent and received per business day by its employees differs from the mean number of emails sent and received per day by corporate employees, which is 101.5. Suppose the depar
> A random sample of final examination grades for a college course follows. Use α = .05 and test to determine whether a normal probability distribution should be rejected as being representative of the population distribution of grades.
> Based on 2017 sales, the six top-selling compact cars are the Honda Civic, Toyota Corolla, Nissan Sentra, Hyundai Elantra, Chevrolet Cruze, and Ford Focus (New York Daily News, http://www.nydailynews.com/autos/street-smarts/best-selling-small-cars-2016-l
> In an effort to make better use of its resources, the New York City Food Bank engaged in lean process improvement. This employee-driven kaizen effort resulted in a new method for packing meals for distribution to needy families. One goal of the process i
> Stable cost reporting in a manufacturing setting is typically a sign that operations are running smoothly. The accounting department at Rockwell Collins, an avionics manufacturer, analyzes the variance of the weekly costs reported by two of its productio
> The grade point averages of 352 students who completed a college course in financial accounting have a standard deviation of .940. The grade point averages of 73 students who dropped out of the same course have a standard deviation of .797. Do the data i
> Is there any difference in the variability in golf scores for players on the LPGA Tour (the women’s professional golf tour) and players on the PGA Tour (the men’s professional golf tour)? A sample of 20 tournament scores from LPGA events showed a standar
> Passenger Volume on Allegiant Airlines. A sample standard deviation for the number of passengers taking a particular Allegiant Airlines flight is 8. A 95% confidence interval estimate of the population standard deviation is 5.86 passengers to 12.62 passe
> A sample of 9 days over the past six months showed that Philip Sherman, DDS, treated the following numbers of patients at his dental clinic: 22, 25, 20, 18, 15, 22, 24, 19, and 26. If the number of patients seen per day is normally distributed, would an
> OrderUp is a service that delivers food that its customers order online from participating restaurants. OrderUp claims consistent delivery times for its deliveries. A sample of 22 meal deliveries shows a sample variance of 1.5. Test to determine whether
> Filling boxes with consistent amounts of its cereals is critical to General Mills’s success. The filling variance for boxes of Count Chocula cereal is designed to be .02 ounces2 or less. A sample of 41 boxes of Count Chocula shows a sample standard devia
> An automobile mileage study tested the following hypotheses. Hypothesis …………………………………………………………………………………………….. Conclusion H0: µ ≥ 25 mpg ………………………………………………………… Manufacturer’s claim supported Ha: µ < 25 mpg ………………………………… Manufacturer’s claim rejected; ave
> Ball bearing manufacturing is a highly precise business in which minimal part variability is critical. Large variances in the size of the ball bearings cause bearing failure and rapid wearout. Production standards call for a maximum variance of .0001 inc
> According to the 2017 Corporate Travel Index compiled by Business Travel News, the average daily cost for business travel in the United States rose to $321 per day (Executive Travel website, https://executivetravel.com/new-business-travel-study-says-aver
> Initial public offerings (IPOs) of stocks are on average underpriced. The standard deviation measures the dispersion, or variation, in the underpricing-overpricing indicator. A sample of 13 Canadian IPOs that were subsequently traded on the Toronto Stock
> Because of staffing decisions, managers of the Gibson-Marimont Hotel are interested in the variability in the number of rooms occupied per day during a particular season of the year. A sample of 20 days of operation shows a sample mean of 290 rooms occup
> Suppose on average a male shaver in Year 1 bought one razor handle and used 17 razor blades in a year and that the price relatives for Year 1 to Year 11 are as appears in the following table. Develop a Male Shaver Expense Index based on weighted price re
> Embassy Publishing Company received a sixchapter manuscript for a new college textbook. The editor of the college division is familiar with the manuscript and estimated a .65 probability that the textbook will be successful. If successful, a profit of $7
> Hemmingway, Inc. is considering a $50 million research and development (R&D) project. Profit projections appear promising, but Hemmingway’s president is concerned because the probability that the R&D project will be successful i
> Warren Lloyd is interested in leasing a new car and has contacted three automobile dealers for pricing information. Each dealer offered Warren a closed-end 36-month lease with no down payment due at the time of signing. Each lease includes a monthly char
> An airline operates a call center to handle customer questions and complaints. The airline monitors a sample of calls to help ensure that the service being provided is of high quality. Ten random samples of 100 calls each were monitored under normal cond
> 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.
> Young Adult magazine states the following hypotheses about the mean age of its subscribers. H0: µ = 28 Ha: µ ≠ 28 If the manager conducting the test will permit a .15 probability of making a Type II error when the true mean age is 29, what sample size sh
> 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 severa
> 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
> 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 x chart for this process if samples of
> A process sampled 20 times with a sample of size 8 resulted in x̅ = 28.5 and R̅ = 1.6. Compute the upper and lower control limits for the x̅ and R charts for this process.
> 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
> 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
> 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 nu
> To inspect incoming shipments of raw materials, a manufacturer is considering samples of sizes 10, 15, and 19. Use the binomial probabilities from Table 5 of Appendix B to select a sampling plan that provides a producer’s risk of α = .03 when p0 is .05 a
> 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 ac
> Repeat exercise 11 for the acceptance sampling plan with η = 20 and c = 1. What happens to the producer’s risk as the acceptance number c is increased? Explain Exercise 11: Consider an acceptance sampling plan with η = 20 and c = 0. Compute the producer
> A special industrial battery must have a life of at least 400 hours. A hypothesis test is to be conducted with a .02 level of significance. If the batteries from a particular production run have an actual mean use life of 385 hours, the production manage
> Consider an acceptance sampling plan with η = 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%.
> For an acceptance sampling plan with η = 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%?
> A process that is in control has a mean of µ = 12.5 and a standard deviation of σ = .8. a. Construct the x̅ control chart for this process if samples of size 4 are to be used. b. Repeat part (a) for samples of sizes 8 and 16. c. What happens to the limit
> 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. Inter
> Compute the price relatives for the R&B Beverages products in exercise 5. Use a weighted average of price relatives to show that this method provides the same index as the weighted aggregate method. Exercise 5: R&B Beverages, Inc., provides a co
> 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
> 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.
> R&B Beverages, Inc., provides a complete line of beer, wine, and soft drink products for distribution through retail outlets in central Iowa. Unit price data for 2015 and 2018 and quantities sold in cases follow. Compute a weighted aggregate index
> 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-per
> Fastenal, the largest fastener distributor in North America, procures an identical drive anchor from three independent suppliers that differ in unit price and quantity supplied. The relevant data for 2016 and 2018 are given in the following table, where
> Suppose the project director for the Hilltop Coffee study (see Section 9.3) asked for a .10 probability of claiming that Hilltop was not in violation when it really was underfilling by 1 ounce (µa = 2.9375 pounds). What sample size would have been recomm
