Is there brand loyalty among car owners in their purchases of gasoline? To help answer the question a random sample of car owners was asked to record the brand of gasoline in their last two purchases (1 = Exxon, 2 = Amoco, 3 = Texaco, and 4 = Other). Use a tabular technique to formulate your answer.
> Refer to Exercise 6.43. A similar analysis produced these joint probabilities. a. What is the probability that a school with an enrollment of less than 300 had at least one violent crime during the year? b. What is the probability that a school that has
> Violent crime in many American schools is an unfortunate fact of life. An analysis of schools and violent crime yielded the table of joint probabilities shown next. If one school is randomly selected find the following probabilities. a. Probability of a
> The issue of health care coverage in the United States is becoming a critical issue in American politics. A large-scale study was undertaken to determine who is and is not covered. From this study, the following table of joint probabilities was produced.
> Is there a relationship between the male hormone testosterone and criminal behavior? To answer this question, medical researchers measured the testosterone level of penitentiary inmates and recorded whether they were convicted of murder. After analyzing
> An expensive restaurant conducted an analysis of the number of people at tables from which the probability distribution was developed. If one table is selected at random determine the probability of the following events. a. Table has more than 4 people
> Many critics of television claim that there is too much violence and that it has a negative effect on society. There may also be a negative effect on advertisers. To examine this issue, researchers developed two versions of a cops-and-robbers made-for-te
> An investor tells you that in her estimation there is a 60% probability that the Dow Jones Industrial Averages index will increase tomorrow. a. Which approach was used to produce this figure? b. Interpret the 60% probability.
> An analysis of fired or laid-off workers, their age, and the reasons for their departure produced the following table of joint probabilities. a. What is the probability that a 25- to 54-yearold employee was laid off or fired because of insufficient work
> To determine whether drinking alcoholic beverages has an effect on the bacteria that cause ulcers, researchers developed the following table of joint probabilities. a. What proportion of people have ulcers? b. What is the probability that a teetotaler (
> A restaurant chain routinely surveys its customers. Among other questions, the survey asks each customer whether he or she would return and to rate the quality of food. Summarizing hundreds of thousands of questionnaires produced this table of joint prob
> The method of instruction in college and university applied statistics courses is changing. Historically, most courses were taught with an emphasis on manual calculation. The alternative is to employ a computer and a software package to perform the calcu
> Refer to Exercise 6.34. Are smoking and lung disease among 60- to 65-year-old men related? Explain. Data from Exercise 6.34: The costs of medical care in North America are increasing faster than inflation, and with the baby boom generation soon to need h
> The costs of medical care in North America are increasing faster than inflation, and with the baby boom generation soon to need health care, it becomes imperative that countries find ways to reduce both costs and demand. The following table lists the joi
> The following table lists the probabilities of unemployed females and males and their educational attainment. a. If one unemployed person is selected at random, what is the probability that he or she did not finish high school? b. If an unemployed femal
> A department store analyzed its most recent sales and determined the relationship between the way the customer paid for the item and the price category of the item. The joint probabilities in the following table were calculated. a. What proportion of pu
> Refer to Exercise 7.40. A previous analysis of historical records found that the mean value of orders for promotional goods is $20, with the company earning a gross profit of 20% on each order. Calculate the expected value of the profit contribution next
> Discrimination in the workplace is illegal, and companies that discriminate are often sued. The female instructors at a large university recently lodged a complaint about the most recent round of promotions from assistant professor to associate professor
> Refer to Exercise 6.28. a. Compute P(A1 or A2). b. Compute P(A2 or B2). c. Compute P(A3 or B1). Data from Exercise 6.28: Suppose we have the following joint probabilities. Compute the marginal probabilities. A, Az A, B, B2 .15 .20 .10 .25 .25 .05
> A quiz contains a multiple-choice question with five possible answers, only one of which is correct. A student plans to guess the answer because he knows absolutely nothing about the subject. a. Produce the sample space for each question. b. Assign proba
> Refer to Exercise 6.28. a. Compute P(A2 ∣B2). b. Compute P(B2 ∣A2). c. Compute P(B1 ∣A2). Data from Exercise 6.28: Suppose we have the following joint probabilities. Compute the marginal probabili
> Suppose we have the following joint probabilities. Compute the marginal probabilities. A, Az A, B, B2 .15 .20 .10 .25 .25 .05
> Determine whether the events are independent from the following joint probabilities. A, Az B, B2 .20 .15 .60 .05
> Suppose that you have been given the following joint probabilities. Are the events independent? Explain. A, Az B, B2 .20 .60 .05 .15
> Refer to Exercise 6.21. Compute the following. a. P(A1 or B1) b. P(A1 or B2) c. P(A1 or A2) Data from Exercise 6.21: Calculate the marginal probabilities from the following table of joint probabilities. A, A, .4 .3 B, B2 .2 .1
> Are the events in Exercise 6.21 independent? Explain. Data from Exercise 6.21: Calculate the marginal probabilities from the following table of joint probabilities. A, A, .4 .3 B, B2 .2 .1
> Refer to Exercise 6.21. a. Determine P(A1 ∣B2). b. Determine P(B2 ∣A1). c. Did you expect the answers to parts (a) and (b) to be reciprocals? In other words, did you expect that P(A1 ∣B2) = 1/P(B2 ∣A1)? Why is this impossible (unless both probabilities a
> To examine the effectiveness of its four annual advertising promotions, a mail-order company has sent a questionnaire to each of its customers, asking how many of the previous year’s promotions prompted orders that would not otherwise h
> Refer to Exercise 6.21. a. Determine P(A1 ∣B1). b. Determine P(A2 ∣B1). c. Did your answers to parts (a) and (b) sum to 1? Is this a coincidence? Explain. Data from Exercise 6.21: Calculate the marginal probabilities from the following table of joint pro
> Calculate the marginal probabilities from the following table of joint probabilities. A, A, .4 .3 B, B2 .2 .1
> Given the following table of joint probabilities, calculate the marginal probabilities. A, Az A3 B, B2 .1 3 .2 .2 .1 .1
> A sportscaster states that he believes that the probability that the New York Yankees will win the World Series this year is 25%. a. Which method was used to assign that probability? b. How would you interpret the probability?
> Refer to Exercise 6.18. The results of the survey are listed next. How Safe is Uber? Responses (%) Very safe 17 Somewhat safe 28 Somewhat unsafe 21 Very unsafe 12 Not sure 22 If
> Uber, the ride-sharing service has been encountering protests mostly from taxi drivers. The taxi industry claims that Uber is more dangerous than other taxis because of the lack of government scrutiny. A survey was conducted where people were asked, “In
> Refer to Exercise 2.55. Here is a list of the top 10 foreign governments that own the U.S. debt (in order of magnitude). Depict these figures with a graph. Government Debt China, m
> Refer to Exercise 6.16. The numbers (in millions) of Americans speaking non-English languages at home are listed next. Language Spoken at Home Millions of Americans Spanish 38.4 Chinese 3.0 Tagalog 1.6 Vietnamese 1.4 F
> As of May 2016 the U.S. government owes $19,190,059,553,782. To whom does the U.S. government owe money? The list is shown below (in $billions). Use a graphical technique to depict these figures. U.S. Individuals and Institutions
> The Gallup poll in Exercise 2.40 asked American adults about their views on economic issues. The survey also asked which political party they supported. 1. Democrat 2. Independent 3. Republican Use a graphical technique to gauge the differences between t
> Refer to Exercise 7.38. Further analysis by the manager revealed that the cost of processing each page of a fax is $.25. Determine the mean and variance of the cost per fax. Data from Exercise 7.38: After an analysis of incoming faxes, the manager of an
> Exercise 2.39 featured a Gallup survey of American adults asking whether they are liberal, moderate or conservative on social issues. In addition, the survey asked respondents whether they considered themselves to be 1. Democrat 2. Independent 3. Republi
> To help determine the need for more golf courses, a survey was undertaken. A sample of 75 self-declared golfers was asked how many rounds of golf they played last year. Draw a histogram and describe what it tells you.
> In addition to asking American adults whether they support keeping the Affordable Care Act the Gallup poll determined whether the respondents were 1. Democrats or 2. Republicans. Determine whether Democrats and Republicans differ in their support of the
> In Exercise 2.35 a Gallup survey asked American adults whether they believed that upperincome people are paying their fair share in federal taxes. Each respondent was also classified as 1. Conservative 2. Moderate 3. Liberal Present a graphical method to
> Exercise 2.34 presented the data from a Pew Research Center survey of American adults describing whether their friends share their political views. Also recorded were the political views of the respondents. The responses are as follows: 1. Consistent co
> Residents of condominiums were recently surveyed and asked a series of questions. Identify the type of data for each question. a. What is your age? b. On what floor is your condominium? c. Do you own or rent? d. How large is your condominium (in square f
> Also recorded was the gender (1 = male, 2 = female) of the respondents. Use a graphical technique to determine whether the choice of light beers differs between genders. Refer to Exercise 2.33. 1. Bud Light 2. Busch Light 3. Coors Light 4. Michelob Light
> In 2010, the total number of prescriptions sold in the United States was 3,676,000 (Source: National Association of Drug Store Chains). The sales manager of a chain of drug stores wanted to determine whether changes in where the prescriptions were filled
> There are 62 million Americans who speak a language other than English at home. The languages are Spanish, Chinese Tagalog (Philippines language), Vietnamese, French, Korean, and others. Suppose that one of these individuals is selected at random. Use se
> In 2009 there were 8,626,000 men and 6,199,000 women who were unemployed at some time during the year. A statistics practitioner wanted to investigate the reason for that unemployment status and whether the reasons differed by gender. A random sample of
> After an analysis of incoming faxes, the manager of an accounting firm determined the probability distribution of the number of pages per facsimile as follows: Compute the mean and variance of the number of pages per fax. 1 3 4 5 7 P(x) .05 .12 20 .
> The associate dean of a business school was looking for ways to improve the quality of the applicants to its MBA program. In particular she wanted to know whether the undergraduate degree of applicants differed among her school and the three nearby unive
> The average loss from robbery in the United States in 2014 (last year available) was $1,227. Suppose that an insurance analyst wanted to know whether the type of robbery differs in the years 1995, 2000, 2005, 2009, and 2014. A random sample of robbery re
> A survey of 50 baseball fans to report the number of games they attended last year. Draw a histogram and describe its shape.
> How do governments spend the tax dollars they collect, and has this changed over the past decade? The following table displays state and local government expenditures for public works in years 1995, 2000, 2005, and 2008 in millions of dollars. Use a grap
> Gallup Organization Date: May 2016 Population: American adults Question: “Describe your views on economic issues.” Responses: 1. Liberal 2. Moderate 3. Conservative a. Determine the frequency and the relative frequency distributions. b. Draw a pie chart
> The placement office at a university regularly surveys the graduates 1 year after graduation and asks for the following information. For each, determine the type of data. a. What is your occupation? b. What is your income? c. What degree did you obtain?
> Gallup Organization Date: May 2016 Population: American adults Question: “Describe your views on social issues.” Responses: 1. Liberal 2. Moderate 3. Conservative a. Determine the frequency and the relative frequency distributions. b. Draw a pie chart an
> Refer to Exercises 6.13 and 6.14. Find the probability of each of the following events. a. The adult is single. b. The adult is not divorced c. The adult is either widowed or divorced. Data from Exercise 6.14: Suppose that in the city in which the survey
> Pew Research Center Date: November 2015 Population: Married, two-parent households with at least one child under 18 Question: How do working parents share the work load at home? Responses: 1. Mom: Full time; Dad: Full time 2. Mom: Part time; Dad: Full ti
> It cost one dollar to buy a lottery ticket, which has five prizes. The prizes and the probability that a player wins the prize are listed here. Calculate the expected value of the payoff. Prize ($) 1 million 200,000 Probability 1/10 million 1/1 milli
> Pew Research Center Date: December 2015 Population: American adults Question 1: “Which Social Class does the Republican Party favor?” Question 2: “Which Social Class does the Democratic Party favor?” (Each question was posed to a different sample.) Respo
> Gallup Organization Date: April 2016 Population: American adults Question: “As I read off some different groups, please tell me if you think they are paying their FAIR share in federal taxes, paying too MUCH or paying too LITTLE? First, how about upperin
> Pew Research Center Date: June 2015 Population: Americans who are most likely to vote, donate to campaigns, and participate directly in politics. (They comprise about 20% of all Americans.) Question: Views of their close friends. Responses: 1. Many close
> Increasing tuition has resulted in some students being saddled with large debts upon 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 graduatio
> Chris Golfnut loves the game of golf. Chris also loves statistics. Combining both passions, Chris records a sample of 100 scores. a. What statistics should Chris compute to describe the scores? b. Calculate the mean and standard deviation of the scores.
> A survey of 60 individuals leaving a mall asked how many stores they entered during this visit to the mall. The figures are listed here. 3 2 4 3 3 9 2 4 3 6 2 2 8 7 6 4 5 1 5 2 3 1 1 7 3 4 1 1 4 8 0 2 5 4 4 4 6 2 2 5 3 8 4
> Refer to Exercise 4.139. In addition to the bone density losses, the ages of the women were also recorded. Compute the coefficient of determination and describe what this statistic tells you. Data from Exercise 4.139: Osteoporosis is a condition in which
> The temperature in December in Buffalo, New York, is often below 40 degrees Fahrenheit (4 degrees Celsius). Not surprisingly, when the National Football League Buffalo Bills play at home in December, coffee is a popular item at the concession stand. The
> Refer to Exercise 6.13. Suppose that in the city in which the survey is conducted, 50% of adults are married, 15% are single, 25% are divorced, and 10% are widowed. a. Assign probabilities to each simple event in the sample space. b. Which approach did y
> Osteoporosis is a condition in which bone density decreases, often resulting in broken bones. Bone density usually peaks at age 30 and decreases thereafter. To understand more about the condition, a random sample of women aged 50 years and over was recru
> The owner of a small firm has just purchased a personal computer, which she expects will serve her for the next 2 years. The owner has been told that she “must” buy a surge suppressor to provide protection for her new hardware against possible surges or
> Refer to Exercise 4.74. Draw histograms of the data. What have you learned? Data from Exercisem 4.74: For many restaurants, the amount of time customers linger over coffee and dessert negatively affects profits. To learn more about this variable, a sampl
> In Exercise 4.71 you calculated quartiles. Draw histograms instead and compare the results. Data from Exercise 4.71: The career-counseling center at a university wanted to learn more about the starting salaries of the university’s graduates. They asked e
> a. Calculate the coefficients of the least squares line for the data in Example 3.7. b. Interpret the coefficients. c. Is this information more useful than the information extracted from the scatter diagram? Analyzing the Relationship between Price a
> Refer to Exercise 3.67. Calculate the coefficient of determination and the least squares line. Is this more informative than the scatter diagram? Data from Exercise 3.67: A very large contribution to profits for a movie theater is the sales of popcorn, s
> How many classes should a histogram contain if the number of observations is 125?
> Refer to Exercise 3.59. Compute the coefficients of the least squares line and compare your results with the scatter diagram. Data from Exercise 3.59: Speed 4 6 8 10 12 Kost 88 124 358 519 699 816 Speed 14 16 18 20 Cost 905 1,521 1,888 2,201 2.
> Calculate the coefficient of determination for Exercise 3.58. Is this more informative than the scatter diagram? Data from Exercise 3.58: Calculus 65 58 93 68 74 81 58 85 Statistics 74 72 84 71 68 85 63 73 Calculus 88 75 63 79 80 54 72 Statistics 79
> We calculated the returns on the NASDAQ Index and the following selected stocks on the NASDAQ Exchange for the period January 2011–December 2015. Adobe Systems (ADBE), Intel (INTC), and Microsoft (MSFT) Calculate the beta coefficient and the coefficient
> We calculated the returns on the NASDAQ Index and the following selected stocks on the NASDAQ Exchange for the period January 2011–December 2015. Costco Wholesale (COST), Dollar Tree (DLTR), and Staples (SPLS) Calculate the beta coefficient and the coeff
> A survey asks adults to report their marital status. The sample space is S = 5single, married, divorced, widowed6 Use set notation to represent the event the adult is not married.
> The manager of a bookstore recorded the number of customers who arrive at a checkout counter every 5 minutes from which the following distribution was calculated. Calculate the mean and standard deviation of the random variable. 1 2 3 4 P(x) .10 .20
> We calculated the returns on the NASDAQ Index and the following selected stocks on the NASDAQ Exchange for the period January 2011–December 2015. Apple (AAPL), Cisco Systems (CSCO), and Oracle (ORCL) Calculate the beta coefficient and the coefficient of
> We calculated the returns on the NASDAQ Index and the following selected stocks on the NASDAQ Exchange for the period January 2011–December 2015. Netflix (NFLX) Determine the average beta coefficient for the stocks in the listed portfolio. Calculate the
> We calculated the returns on the NASDAQ Index and the following selected stocks on the NASDAQ Exchange for the period January 2011–December 2015. Expedia (EXPE) Calculate the beta coefficient and the coefficient of determination for the listed stock and
> We calculated the returns on the NASDAQ Index and the following selected stocks on the NASDAQ Exchange for the period January 2011–December 2015. Amazon (AMZN) Calculate the beta coefficient and the coefficient of determination for the listed stock and i
> Refer to Exercise 6.124. Suppose the student informs the professor that he can see only one coin and it shows tails. What is the probability that the other coin is also tails? Data from Exercise 6.124: In a class on probability, a statistics professor fl
> In a class on probability, a statistics professor flips two balanced coins. Both fall to the floor and roll under his desk. A student in the first row informs the professor that he can see both coins. He reports that at least one of them shows tails. Wha
> A union’s executive conducted a survey of its members to determine what the membership felt were the important issues to be resolved during upcoming negotiations with management. The results indicate that 74% of members felt that job security was an impo
> A statistics professor and his wife are planning to take a 2-week vacation in Hawaii, but they can’t decide whether to spend 1 week on each of the islands of Maui and Oahu, 2 weeks on Maui, or 2 weeks on Oahu. Placing their faith in random chance, they i
> A safety expert wants to determine the proportion of cars in his state with worn tire treads. The state license plate contains six digits. Use Excel to generate a sample of 20 cars to be examined.
> How does level of affluence affect health care? To address one dimension of the problem, a group of heart attack victims was selected. Each was categorized as a low-, medium-, or high-income earner. Each was also categorized as having survived or died. A
> You have been given the choice of receiving $500 in cash or receiving a gold coin that has a face value of $100. However, the actual value of the gold coin depends on its gold content. You are told that the coin has a 40% probability of being worth $400,
> A customer-service supervisor regularly conducts a survey of customer satisfaction. The results of the latest survey indicate that 8% of customers were not satisfied with the service they received at their last visit to the store. Of those who are not sa
> Casino Windsor conducts surveys to determine the opinions of its customers. Among other questions, respondents are asked to give their opinion about “Your overall impression of Casino Windsor.” The responses are Excell
> In Canada, criminals are entitled to parole after serving only one-third of their sentence. Virtually all prisoners, with several exceptions including murderers, are released after serving two-thirds of their sentence. The government has proposed a new l
> A statistics professor believes that there is a relationship between the number of missed classes and the grade on his midterm test. After examining his records, he produced the following table of joint probabilities. a. What is the pass rate on the mid
> A telemarketer sells magazine subscriptions over the telephone. The probability of a busy signal or no answer is 65%. If the telemarketer does make contact, the probability of 0, 1, 2, or 3 magazine subscriptions is .5, .25, .20, and .05, respectively. F
> In a four-cylinder engine there are four spark plugs. If any one of them malfunctions, the car will idle roughly and power will be lost. Suppose that for a certain brand of spark plugs the probability that a spark plug will function properly after 5,000
> Refer to Exercise 6.111. Suppose that you are told that the drug is effective. What is the probability that the drug taker is a man? Data from Exercise 6.111: The effect of an antidepressant drug varies from person to person. Suppose that the drug is eff
> Laser surgery to fix shortsightedness is becoming more popular. However, for some people, a second procedure is necessary. The following table lists the joint probabilities of needing a second procedure and whether the patient has a corrective lens with
