The New York Times published an article that included a statement that chocolate “moves toward its rightful place in the food pyramid, somewhere in the high-tone neighborhood of red wine, fruits and vegetables, and green tea.” It was noted that studies showed that eating chocolate was associated with increased levels of antioxidants in blood and that chocolate flavonoids, which are antioxidants, have been associated with decreased risk of heart disease and stroke. Mars Inc. (the candy company) and the Chocolate Manufacturers Association financed much of the research.
> Names, such as Katrina and Sandy, used to identify different hurricanes.
> In a CBS News/New York Times poll of 1289 adults nationwide, asking whether they favor or oppose teachers and school officials carrying guns in school, 57% were opposed. The margin of error is 4 percentage points.
> “Categories” 1, 2, 3, 4, and 5, used to describe the intensity of hurricanes
> Types of movies (drama, comedy, etc.)
> Scores of 0%, 1%, 2%, … 100% used to rate the quality of a movie.
> Weights of Corvettes that are currently registered in California.
> Body temperatures in Fahrenheit of all giraffes in Kenya.
> Number of stars in each galaxy in the universe.
> The movie ratings by a critic, which are expressed as 0 stars, ¹∕² star, 1 star, and so on
> The speeds of commercial aircraft in the air at any one point in time.
> Number of commercial aircraft in the air at any point in time.
> The times (years) it takes college students to earn a bachelor’s degree, such as 4 years, 4¹∕² years, 5 years, and so on.
> 106 adults are randomly selected and tested for their body temperatures. Based on that sample, it is estimated that the average (mean) body temperature is 98.2°F with a margin of error of 0.1°F.
> The exact times required by students to reach their first class.
> The arrival delay times recorded for a random sample of flights from New York to Chicago.
> The number of likes for a specific post on Facebook.
> The page counts of textbooks used in college courses.
> The weights of textbooks used in college courses.
> The area codes (such as 617) of the telephone numbers of survey subjects
> The SAT scores of randomly selected applicants to colleges.
> The number of households with a television in use when surveyed by Nielsen Media Research
> The television shows being watched by households surveyed by Nielsen Media Research
> In studying different prehistoric societies, an archeologist measures head circumferences of skulls.
> In a Harris Interactive survey of 1006 adults, 96% say that they wash their hands when in a public restroom. The margin of error is 3 percentage point.
> The responses (yes, no, or no response) from survey subjects when asked a question
> Olympic athletes are categorized according to the sport in which they compete, such as track and field, cycling, or gymnastics.
> Measurements of blood alcohol concentration (BAC), which represent how much alcohol is found in blood
> In a simple random sample of adults, the pulse rate is measured for each subject.
> The common blood groups are A, B, AB, and O.
> The year 2050 will be halfway through the twenty-first century.
> Los Angeles reached a temperature of 100°F today, which was twice as hot as the 50°F in Denver.
> ZIP codes are quantitative data because, in general, lower numbers are in the east and higher numbers are in the west
> Why are self-selected surveys almost always prone to participation bias?
> Describe and contrast selection bias and participation bias in sampling.
> USA Today reported that among 6028 adults observed in restrooms, 85% washed their hands. The margin of error is 1 percentage point.
> What is peer review? How is it useful?
> Briefly describe the eight guidelines for critically evaluating a statistical study
> A USA Today headline reported “China thrown off balance as boys outnumber girls,” and an accompanying graph showed that for every 100 girls born in China, 116.9 boys are born.
> A USA Today headline reported “More companies try to bet on forecasting weather.” The article gave examples of companies believing that long-range forecasts are reliable, and four companies were cited.
> CNN reports on a Zagat survey of America’s top restaurants, which found that “only nine restaurants achieved a rare 29 out of a possible 30 rating and none of those restaurants are in the Big Apple.”
> A USA Today “Snapshot” reported that the percentage of people with diabetes who don’t know that they have diabetes is “1 in 4.” The source was given as the American Diabetes Association.
> “Sex more important than jobs” A survey found that 82% of 500 people interviewed by phone ranked a satisfying sex life as important or very important, while 79% ranked job satisfaction as important or very important (Associated Press).
> “Drugs shown in 98 percent of movies” A “government study” claims that drug use, drinking, or smoking was depicted in 98% of the top movie rentals (Associated Press).
> A Gallup poll asked the following two questions: • Do you favor a tax cut or “increased spending on other government programs”? Result: 75% for the tax cut. • Do you favor a tax cut or “spending to fund new retirement savings accounts, as well as incre
> Princeton Survey Research Associates did a study for Newsweek magazine illustrating the effects of wording in a survey. Two questions were asked. • Do you personally believe that abortion is wrong? • Whatever your own personal view of abortion, do you
> In a Pew Research Center poll of 1501 randomly selected adults in Latin America, 77% said that global warming is already harming people around the world. The margin of error is 2 percentage points.
> You plan to conduct a survey to find the percentage of people in your state who can name the lieutenant governor, who plans to run for the United States Senate. You obtain addresses from a list of property owners in the state and you mail a survey to 850
> You receive a call in which the caller claims to be conducting a national opinion research poll. You are asked if your opinion about Congressional candidate John Sweeney would change if you knew that Sweeney once had a car crash while driving under the i
> When author Shere Hite wrote Women and Love: A Cultural Revolution in Progress, she based conclusions about the general population of all women on 4500 replies that she received after mailing 100,000 questionnaires to various women’s groups.
> A survey included this question: “Do you favor or oppose raising taxes to be used for wasteful spending on science research projects?”
> An independent research firm conducts a survey of adults who view movies. Each interview subject is asked this question: “Is there is too much violence in movies?”
> After conducting a survey about texting and driving, a researcher discovers that the practice is very dangerous and believes that he is doing a public service by exaggerating the results of the study
> A journal article reports very favorable results from tests of a statin designed to lower cholesterol levels. The researchers received funding from the pharmaceutical company that produces the statin.
> A clinical trial of a treatment intended to help smokers stop smoking was conducted. The sample consisted of male college students, and the trial showed that, for American adults, the treatment is effective.
> Researchers conclude that the drought mitigation system used to conserve water in California is more effective than a competing system used in Hawaii.
> In an Accountemps survey of 150 senior executives, 47% said that the most common job interview mistake is to have little or no knowledge of the company where the applicant is being interviewed.
> In a survey of 1200 college students, each was asked whether he or she was a good person.
> A clothing company sponsored a survey showing that dressing stylishly is critically important for success in a job interview.
> My experiment proved beyond a doubt that vitamin C can reduce the severity of colds, because I controlled the experiment carefully for every possible confounding variable.
> A pollster plans to improve survey results by only conducting polls in which the margin of error is zero.
> If you use a large enough sample, it does not matter if the sample is biased, so the treatment must have practical significance.
> More than 1 million people sent texts in response to a TV survey question, so this survey result is clearly more valid than any survey of a few hundred people.
> Which siding lasts longer on a home: aluminum, vinyl, or wood?
> A company is developing a new battery for smartphones, and it is claimed that the new battery lasts significantly longer than those currently in use.
> Does the herb echinacea help prevent colds?
> Does listening to Beethoven make teenagers more intelligent?
> In a test of the effectiveness of garlic for lowering cholesterol, 47 adult subjects were treated with Garlicin, which is garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes in the subjects’ lev
> Describe the five basic steps in a statistical study, and give an example of their application.
> The worldwide market share for the Chrome web browser was 69.52% in March 2019. Source: Data extracted from netmarketshare.com. Suppose that you decide to select a sample of 100 students at your university and you find that 60 use the Chrome web browser.
> You are the production manager at a parachute manufacturing company. Parachutes are woven in your factory using a synthetic fiber purchased from one of four different suppliers. The strength of these fibers is an important characteristic that ensures qua
> The major stock market indexes had weak results in 2018. The mean one-year return for stocks in the S&P 500, a group of 500 very large companies, was -6.24%. The mean one-year return for the NASDAQ, a group of 3,200 small and medium-sized companies, was
> In a recent year, 46% of Google searches were one or two words, while 21% of Google searches were five or six words. Source: Wordstream Biog, "27 Google Search Statistics You Should Know in 2019 (+ Insights!)," bit.ly/2GxpUlv. If a sample of I 0 Google s
> A sports statistician seeks to evaluate NBA team statistics for a recent year. The statistician collects data for wins and points scored, field goal percentage, opponent field goal percentage, three-point field goal percentage, free throw percentage, reb
> Examine Zarca Interactive's "Sample Employee Satisfaction Survey/Sample Questions for Employee Satisfaction Survey," available at bit.Iy/21qjl6F. a. Give an example of a categorical variable included in the survey. b. Give an example of a numerical varia
> A pet food company has the business objective of having the weight of a can of cat food come as close to the specified weight as possible. Realizing that the size of the pieces of meat contained in a can and the can fill height could impact the weight of
> The Super Bowl is a big viewing event watched by close to 200 million Americans, so it is also a big event for advertisers. The file Super Bowl Ad Rating contains the rating of ads that ran between the opening kick-off and the final whistle. Source: Data
> The file Mobile S contains the overall download and upload speeds in Mbps for eight carriers in the U.S. Source: Data extracted from Tom's Guide, "Fastest Wireless Network 201 9: It's Not Even Close," bit.ly/2PcGiQE. a. Calculate the covariance between d
> General Electric (GE) is one of the world's largest companies; it develops, manufactures, and markets a wide range of products, including medical diagnostic imaging devices, jet engines, Lighting products, and chemicals. In 2017, the stock price rose 0.0
> The file Engines contains the data for a study that explored if automobile engine torque could be predicted from engine speed (in RPM, revolutions per minute). Source: Data extracted from Y. Chen et al., "Cluster-Based Profile Analysis in Phase I," Journ
> A hotel wanted to develop a new system for delivering room service breakfasts. In the current system, an order form is left on the bed in each room. If the customer wishes to receive a room service breakfast, he or she places the order form on the doorkn
> Accounting Today identified top accounting firms in 10 geographic regions across the United States. All 10 regions reported growth in a recent year. The Southeast and Gulf Coast regions reported growths of 12.49% and 9.78%, respectively. A characteristic
> An operations manager wants to examine the effect of air-jet pressure (in pounds per square inch [psi]) on the breaking strength of yarn. Three different levels of air-jet pressure are to be considered: 30 psi, 40 psi, and 50 psi. A random sample of 18 y
> The following is a set of data from a sample of n = 11 items: a. Compute the covariance. b. Compute the coefficient of correlation. c. How strong is the relationship between X and Y? Explain.
> Thirty companies comprise the DJIA. Just how big are these companies? One common method for measuring the size of a company is to use its market capitalization, the product of multiplying the number of stock shares by the price of a share of stock. On Ap
> The file Credit Scores contains the average credit scores of people from 2,750 American cities. Source: Data extracted from bit.ly/2oCgnbi. a. Select five different samples of n = 2, n = 5, n = 15, and n = 30. b. Compute the sample mean of each sample. D
> The file Cigarette Tax contains the state cigarette tax (in $) for each of the 50 states and the District of Columbia as of January 1, 2019. a. Calculate the population mean and population standard deviation for the state cigarette tax. b. Interpret the
> Interns report that when deciding on where to work, career growth, salary and compensation, location and commute, and company culture and values are important factors to them. According to reports by interns to Glassdoor, the mean monthly pay of interns
> The file McDonalds Stores contains the number of McDonald's stores per 100,000 population located in each of the 50 U.S. states as of September 13, 2018. Source: Data extracted from Usatoday.com, "ls your state 'lovin' it'?" bit.ly/2vFGoay. a. Calculate
> The file Domestic Beer contains the percentage alcohol, number of calories per 12 ounces, and number of carbohydrates (in grams) per 12 ounces for 157 of the best-selling domestic beers in the United States. Determine whether each of these variables appe
> Researchers wanted to investigate the relationship between employment and accommodation capacity in the European travel and tourism industry. The file European Tourism contains a sample of 28 European countries. Variables included are the number of jobs
> How do regression trees differ from classification trees?
> The file Work Hours Needed contains the average number of hours worked necessary for three people to afford to attend an NBA game, inclusive of parking and food and beverage costs, at each of the 30 NBA basketball arenas during a recent season. Source: f
> The Internet has become a crucial marketing channel for business. According to a recent study, 91% of retail brands use two or more social media channels for business. Source: Data extracted from Brandwatch, "123 Amazing Social Media Statistics and Facts
> For the year 201 8, the stock market in Germany had a mean return of - 12.53% in 2018. Assume that the returns for stocks on the German stock market were distributed normally, with a mean of - 12.53% and a standard deviation of 10. If you select an indiv
> A toll-free phone number is available from 9 A.M. to 9 P.M. for your customers to register complaints about a product purchased from your company. Past history indicates that a mean of 0.8 calls is received per minute. a. What properties must be true abo
> Refer to Problem 5.27. If you purchased a Toyota in the 2019 model year, what is the probability that in the past 12 months the car had; a. zero problems? b. two or fewer problems? c. Compare your answers in (a) and (b) to those for the Ford in Problem 5
> J.D. Power and Associates calculates and publishes various statistics concerning car quality. The dependability score measures problems experienced during the past 12 months by owners of vehicles (2019). For these models of cars, Ford had 1.48 problems p
> How long does it take to download a two-hour HD movie from a streaming media site? According to Fastmetrics's "Download Speed Comparison Table," bit.Iy/lEONXKY, downloading such a movie using a 100 Mbps Internet connection should take about 4.5 minutes.
> The U.S. Department of Transportation maintains statistics for mishandled bags. In January 2019, American Airlines mishandled 0.90 bags per day. What is the probability that in the next month, American Airlines will have; a. no mishandled bags? b. at lea
> In Problem 14.6, you used full-time voluntary turnover (%), and total worldwide revenue ($billions) to predict number of full-time job openings (stored in Best Companies). Develop a regression model to predict the number of full-time job openings that in
