Question: The U.S. Bureau of Labor Statistics

> In deciding where to invest her retirement fund, an investor recorded the weekly returns of two portfolios for 1 year. Can we conclude that portfolio 2 is riskier than portfolio 1?

> In Exercise 12.80 we described the problem of whether to change all the light bulbs at Yankee Stadium or change them one by one as they burn out. There are two brands of bulbs that can be used. Because both the mean and the variance of the lengths of lif

> A new highway has just been completed and the government must decide on speed limits. There are several possible choices. However, on advice from police who monitor traffic the objective was to reduce the variation in speeds, which it is thought to contr

> A statistics professor hypothesized that not only would the means vary, but also so would the variances if the business statistics course was taught in two different ways but had the same final exam. He organized an experiment wherein one section of the

> An operations manager who supervises an assembly line has been experiencing problems with the sequencing of jobs. The problem is that bottlenecks are occurring because of the inconsistency of sequential operations. He decides to conduct an experiment whe

> The manager of a dairy is in the process of deciding which of two new carton-filling machines to use. The most important attripute is the consistency of the fills. In a preliminary study she measured the fills in the 1-liter carton and listed them here.

> Random samples from two normal populations produced the following statistics: a. Estimate with 95% confidence the ratio of the two population variances. b. Repeat part (a) changing the sample sizes to n1 = 25 and n2 = 25. c. Describe what happens to the

> Random samples from two normal populations produced the following statistics: a. Can we infer at the 10% significance level that the two population variances differ? b. Repeat part (a) changing the sample sizes to n1 = 15 and n2 = 15. c. Describe what ha

> Refer to Example 13.2. The actual after and before operating incomes were recorded. a. Test to determine whether there is enough evidence to infer that for companies where an offspring takes the helm there is a decrease in operating income. b. Is there s

> Discuss why the experiment in Example 13.5 produced a significant test result whereas the one in Exercise 13.103 did not.

> From January 1 to December 31, 2011, there were 5,086 bank robberies in the United States. The percentage of that total for each day of the week is listed next. The number of robberies per day for the first two months of 2016 was recorded. Can we infer t

> Refer to Examples 13.4 and 13.5. Suppose that another experiment is conducted. Finance and marketing MBA majors were matched according to their undergraduate GPA. As in the previous examples, the highest starting salary offers were recorded. Can we infer

> Refer to Exercises 13.33 and 13.101. Explain why the matched pairs experiment produced significant results whereas the independent samples t-test did not. Data from Exercise 13.33: Tire manufacturers are constantly researching ways to produce tires that

> Refer to Exercise 13.33. Suppose now we redo the experiment in the following way. On 20 randomly selected cars, one of each type of tire is installed on the rear wheels and as before, the cars are driven until the tires wear out. The number of miles unti

> Every April Americans and Canadians fill out their tax return forms. Many turn to tax preparation companies to do this tedious job. The question arises, Are there differences between companies? In an experiment two of the largest companies were asked to

> Telemarketers obtain names and telephone numbers from several sources. To determine whether one particular source is better than a second, a random sample of names and numbers from the two different sources was obtained. For each potential customer, a st

> Quik Lube is a company that offers oil change service while the customer waits. Its market has been broken down into the following segments: 1. Working men and women too busy to wait at a dealer or service center 2. Spouses who work in the home 3. Retire

> The market for breakfast cereals has been divided into several segments related to health. One company identified a segment as those adults who are health conscious. The marketing manager would like to know whether this segment is more likely to purchase

> A Gallup survey asks a random sample of American adults this question. “In this country, are you satisfied or dissatisfied with your freedom to choose what you do with your life?” The responses are 1 = satisfied, 2 = dissatisfied. The survey results from

> Surveys of workers asked a series of questions from which each was categorized as either 1 = thriving, 2 = struggling, 3 = suffering. Each respondent was also asked whether they worked for the federal government or a private sector employer. Is there suf

> In June 2016 the United Kingdom voted to leave the European Union. As is the case in the United States, pollsters conducted exit polls and asked how each respondent voted (1 = remain, 2 = leave) and recorded the age category (1 = 18 – 24, 2 = 25 – 49, 3

> An aging pitcher has recorded the following pitch distribution over his long career from 1995 to 2014. 1. Fast ball 52% 2. Curve ball 19% 3. Slider 15% 4. Changeup 14% However, undergoing a surgery to repair a tendo

> Refer to Exercise 13.159. The fan also recorded the calls on pitches that were in the strike zone and the batter did not swing (1 = ball, 2 = strike). Can we infer from the data that there is a difference in the error rate of making calls on pitches in t

> In Exercise 9.59 we pointed out that most televised baseball games display a pitch tracker that shows whether the pitch was a ball or a strike, which in turn shows whether the umpire made the correct call. Suppose a fan kept track of a random sample of c

> To measure the cardiovascular health of Canadians, cardiologists developed the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) health index. A score of 1 is assigned for each of the following cardiovascular health factors and behaviors:

> Refer to Exercise 13.156. In 2700 of the resumes the religion mentioned was one of the mainstream religions. However, 500 resumes made reference to a made-up religion – Wallonian. The religious designation (1 = mainstream religion, 2 = Wallonian) was rec

> An experiment conducted by members of the Religious Affiliation and Hiring Discrimination Organization to determine what shouldn’t be in the resume should be of interest to students preparing resumes in search of summer or permanent jobs. The experiment

> One of the issues in the U.S. presidential election in 2016 was the Keystone XL pipeline, which would send Canadian oil to the refineries in Texas. Pew Research Center conducted a survey of American adults and asked each whether he or she was in favor (

> In Chapters 3 and 4, we described the issue of global warming pointing out that the Earth has not warmed since 1998, explaining why the media now refer to the problem as climate change, and that there is a weak linear relationship between temperature ano

> Are Americans becoming more unhappy at work? A survey of Americans in 2008 and again this year asked whether he or she was satisfied with their jobs (1 = No, 2 = Yes). Can we infer that more Americans are unhappy compared to 2008?

> Parents often urge their children to get more education, not only for the increased income but to perhaps work less hard. In a survey, a random sample of Canadians were asked whether they work 11 or more hours a day (1 = No, 2 = Yes) and whether they com

> An operations manager of a computer chip maker is in the process of selecting a new machine to replace several older ones. Although technological innovations have improved the production process, it is quite common for the machines to produce defective c

> Refer to Exercise 15.15. After an entire season of pitches, the following proportions for all pitches were observed. A rookie pitcher starts his first game and the pitch outcome was recorded using the codes. Is there enough evidence at the 5% significan

> It has been estimated that the oil sands in Alberta Canada contains 2 trillion barrels of oil. However, recovering the oil damages the environment. A survey of Canadians and Americans asked, What is more important to you with regard to the oilsands, envi

> Has the illicit use of drugs decreased over the past 10 years? Government agencies have undertaken surveys of Americans 12 years of age and older. Each was asked whether he or she used drugs at least once in the previous month. The results of this year’s

> An insurance company is thinking about offering discounts on its life insurance policies to nonsmokers. As part of its analysis, the company randomly selects 200 men who are 60 years old and asks them whether they smoke at least one pack of cigarettes pe

> Automobile magazines often compare models and rate them in various ways. One question that is often asked of car owners, Would you buy the same model again? Suppose that a researcher for one magazine asked a random sample of Lexus owners and a random sam

> The objective in Exercise 13.165 was to determine whether various market segments were more likely to use the QuikLube service. Included with the data is also the age (in months) of the car. Do the data allow us to conclude that there are differences in

> Exercise 13.21 addressed the problem of determining whether the distances young (under 25) males and females drive annually differ. Included in the data is also the number of accidents that each person was involved in the past 2 years. Responses are 0, 1

> In Exercise 12.132 marketing managers for the JC Penney department store chain segmented the market for women’s apparel on the basis of personal and family values. The segments are Conservative, Traditional, and Contemporary. Recall that the classificati

> A random sample of 175 people who had lunch at a company cafeteria were offered a brownie. Some were handed the brownie on a fine piece of china, others were given the brownie on a paper plate, and others were given the brownie on a paper napkin. Each pe

> Deskbound secretaries were employed in this experiment. Clear-lidded candy dished filled with 30 Hershey’s Kisses were placed in three different locations. The first location was the secretary’s desk, the second was the top-left drawer in the secretary’

> This experiment consisted of graduates students given either a medium-sized 17-ounce bowls or large-sized 34-ounce bowls. Each student was invited to take as much of four different flavors of ice cream as he or she wanted. The size of the scoop also vari

> Pitch trackers allow baseball fans watching televised games to see whether an umpire made the correct call. After tracking all pitches over an entire season, the following probabilities were recorded. A new umpire has just started and the pitch tracker

> A study described in the British Medical Journal (January 2004) sought to determine whether exercise would help extend the lives of patients with heart failure. A sample of 801 patients with heart failure was recruited; 395 received exercise training and

> The National Center for Charitable Statistics estimates that individual giving in the United States in 2014 was $258.51 billion. A study to determine who gave and how much they gave was undertaken. A random sample of individuals who gave to charities was

> Automobile insurance companies use statistics to determine their premiums. The premiums are proportional to the risks and costs of accidents. Suppose that an economist conducted a study that looked at miles driven in the previous year, ages of the driver

> St Catharine’s-Niagara, Kitchener- Cambridge-Waterloo. Brantford, Guelph, London, and Windsor are relatively small cities in Southwest Ontario. Because of their size the expectation is that the time it takes to get from home to work would not be large. T

> Refer to Exercise 14.135. Do Americans spend more on health care as they age? To answer the question, economists turned to the Bureau of Labor Statistics to measure how much Americans in the following age groups spend annually on health care. (1) 55–64

> Each year Michigan State University’s Collegiate Employment Research Institute tracks starting salaries of graduates. The Institute recorded the starting salaries of the following engineers: chemical, civil, computer, electrical, and mechanical. a. Is th

> Another useful measure of Americans’ beliefs about the state of the economy is the age at which they believe they will retire. If nonretired people believe that they will need to work longer to be able to afford their lifestyle after retirement it likely

> Does the day a house is listed for sale affect how long it takes for the sale to be completed or its selling price? A study conducted by economists attempted to answer the question. A random sample of houses that sold in a major city was studied. The num

> Refer to Exercise 14.129. A similar study determined the monthly household income of households headed by 25- to 34-year-olds with only a high school diploma. The incomes were converted to 2012 dollars. a. Is there sufficient evidence to infer that house

> In an election held last year that was contested by three parties. Party A captured 31% of the vote, party B garnered 51%, and party C received the remaining votes. A survey of 1,200 voters asked each to identify the party that they would vote for in the

> Refer to Exercise 14.129. A similar study was conducted for Bachelor’s degrees. a. Can we infer from the data that incomes differed for 25- to 34-year-olds with Bachelor’s degrees between the three periods? b. Are the required conditions satisfied? Expla

> How have 25- to 34-year-olds with university degrees fared financially since 1984? To answer this question, the Pew Research Center conducted surveys in 1984, 1996, and 2009 recording monthly earnings for graduates with three different types of degrees.

> A random sample of 500 teenagers were grouped in the following way: ages 13–14, 15–17, and 18–19. Each teenager was asked to record the number of Facebook friends each had. Is there sufficient evidence to infer that there are differences in the number of

> Millions of North Americans spend up to several hours a day commuting to and from work. Other than the wasted time, are there other negative effects associated with fighting traffic? A study by Statistics Canada may shed light on the issue. A random samp

> Stock market investors are always seeking the “Holy Grail,” a sign that tells them the market has bottomed out or achieved its highest level. There are several indicators. One is the buy signal developed by Gerald Appel, who believed that a bottom has be

> When the stock market has a large 1-day decline, does it bounce back the next day or does the bad news endure? To answer this question, an economist examined a random sample of daily changes to the Toronto Stock Index (TSE). He recorded the percent chang

> Virtually all restaurants attempt to have three “seatings” on weekend nights. Three seatings means that each table gets three different sets of customers. Obviously, any group that lingers over dessert and coffee may result in the loss of one seating and

> Studies indicate that single male investors tend to take the most risk, whereas married female investors tend to be conservative. This raises the question, which does best? The risk-adjusted returns for single and married men, and for single and married

> Increasing tuition has resulted in some students being saddled with large debts on graduation. To examine this issue, a random sample of recent graduates was asked to report whether they had student loans, and if so, how much was the debt at graduation.

> Are babies who are exposed to music before their birth smarter than those who are not? And, if so, what kind of music is best? Researchers at the University of Wisconsin conducted an experiment with rats. The researchers selected a random sample of pregn

> License records in a county reveal that 15% of cars are subcompacts (1), 25% are compacts (2), 40% are midsize (3), and the rest are an assortment of other styles and models (4). A random sample of accidents involving cars licensed in the county was

> Many of you reading this page probably learned how to read using the whole-language method. This strategy maintains that the natural and effective way is to be exposed to whole words in context. Students learn how to read by recognizing words they have s

> It is important for salespeople to be knowledgeable about how people shop for certain products. Suppose that a new car salesman believes that the age and gender of a car shopper affect the way he or she makes an offer on a car. He records the initial off

> On reconsidering the experiment in Exercise 14.117, the psychologist decides that the age of the child may influence the attention span. Consequently, the experiment is redone in the following way. Three 10-year-olds, three 9-year-olds, three 8-year-olds

> In marketing children’s products, it is extremely important to produce television commercials that hold the attention of the children who view them. A psychologist hired by a marketing research firm wants to determine whether differences in attention spa

> The editor of the student newspaper was in the process of making some major changes in the newspaper’s layout. He was also contemplating changing the typeface of the print used. To help himself make a decision, he set up an experiment in which 20 individ

> The possible imposition of a residential property tax has been a sensitive political issue in a large city that consists of five boroughs. Currently, property tax is based on an assessment system that dates back to 1950. This system has produced numerous

> To help high school students pick a major, a company called PayScale surveys graduates of a variety of programs. In one such survey, graduates of the following degree programs were asked what their annual salaries were after working at least 10 years in

> Each year billions of dollars are lost because of worker injuries on the job. Costs can be decreased if injured workers can be rehabilitated quickly. As part of an analysis of the amount of time taken for workers to return to work, a sample of male blue-

> The marketing department of a firm that manufactures office furniture has ascertained that there is a growing market for a specialized desk that houses the various parts of a computer system. The operations manager is summoned to put together a plan that

> Refer to Example 12.6. In segmenting the breakfast cereal market, a food manufacturer uses health and diet consciousness as the segmentation variable. Four segments are developed: 1. Concerned about eating healthy foods 2. Concerned primarily about weigh

> Financial managers are interested in the speed with which customers who make purchases on credit pay their bills. In addition to calculating the average number of days that unpaid bills (called accounts receivable) remain outstanding, they often prepare

> Refer to Exercise 12.132. The women in the survey were also asked to define value by identifying what they considered to be the most important attribute of value. The responses are: 1. Price 2. Quality 3. Fashion The responses and the classifications of

> Exercise 12.132 described the market segments defined by JC Penney. Another question included in the questionnaire that classified the women surveyed was asked whether each worked outside the home. The responses were: 1. No 2. Part-time job 3. Full-time

> Exercise 2.64 described the survey the Red Lobster Restaurant chain conducts to monitor the performance of individual restaurants. One of the questions asks customers to rate the overall quality of their last visit. The listed responses are Poor (1), Fai

> Exercises 2.33 and 2.49 described a survey that took a random sample of 285 graduating students and asked each to report which of the following is their favorite light beer: 1 =Bud Light, 2 = Busch Light, 3 = Coors Light, 4 = Michelob Light, 5 = Miller L

> Exercise 2.46 asked the question: Are you more likely to smoke if your parents smoke? To shed light on the issue, a sample of 20- to 40-yearold people was asked whether they smoked and whether their parents smoked. The results are stored the following wa

> Exercise 2.65 described a survey of the business school graduates undertaken by a university placement office. The respondents reported (among other questions) gender (1 = Female, 2 = Male) and area of employment (1= Accounting, 2 = Finance, 3 = General

> Example 12.5 described exit polls wherein people are asked whether they voted for the Democrat or Republican candidate for president. The surveyors also record gender (1 = Female, 2 = Male), educational attainment (1 = Did not finish high school, 2 = Com

> Exercise 13.164 described a survey of adults wherein, on the basis of several probing questions, each was classified as either a memberof the health conscious group (code = 1) or not (code = 2) and whether he or she buys Special X (1 = No, 2 = Yes). Addi

> Exercise 12.111 described a study to determine whether viewers (older than 50) of the network news had contacted their physician to ask about one of the prescription drugs advertised during the newscast. The responses (1 = No, 2 = Yes) were recorded. Als

> Refer to Exercise 12.110. Determine whether there is enough evidence to infer thatthere are differences in the choice of Christmas tree between the three age categories. Data from Exercise 12.110: An important decision faces Christmas holiday celebrator

> Pat Statsdud is about to write a multiple- choice exam but as usual knows absolutely nothing. Pat plans to guess one of the five choices. Pat has been given one of the professor’s previous exams with the correct answers marked. The correct choices were r

> Repeat Exercise 15.1 with the following frequencies: Cell 1 2 3 4 5 Frequency 6 16 21 18 14 Data from Exercise 15.1: Consider a multinomial experiment involving n = 300 trials and k = 5 cells. The observed frequencies resulting from the e

> The random variable x is normally distributed with mean µ = 74 and standard deviation σ = 8. Find the indicated probability. P(72 < x < 82)

> The random variable x is normally distributed with mean µ = 74 and standard deviation σ = 8. Find the indicated probability. P(60 < x < 70)

> The random variable x is normally distributed with mean µ = 74 and standard deviation σ = 8. Find the indicated probability. P(x > 71.6)

> The random variable x is normally distributed with mean µ = 74 and standard deviation σ = 8. Find the indicated probability. P(x > 80)

> The random variable x is normally distributed with mean µ = 74 and standard deviation σ = 8. Find the indicated probability. P(x < 55)

> The random variable x is normally distributed with mean µ = 74 and standard deviation σ = 8. Find the indicated probability. P(x < 84)

> Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability. P(z < 0 or z > 1.68)

> Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability. P(z < -2.50 or z > 2.50)

> Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability. P(0.42 < z < 3.15)

> Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability. P(-2.15 < z < 1.55)

> Find the expected net gain to the player for one play of the game. It costs $25 to bet on a horse race. The horse has a 1/8 chance of winning and a 1/4 chance of placing 2nd or 3rd. You win $125 if the horse wins and receive your money back if the horse

> Find the indicated probability using the standard normal distribution. If convenient, use technology to find the probability. P(z > -0.74)