Question: The value of monthly U.S. exports

> Calculate the coefficient of correlation of the amount of education of the respondents and their spouses (EDUC and SPEDUC). What does this statistic tell you about the relationship between the two variables?

> Are there differences between the three categories of race with respect to working for the government or working in the private sector? Draw a graph to depict the differences.

> The following distributions of X and of Y have been developed. If X and Y are independent, determine the joint probability distribution of X and Y . 0 1 2 y 1 2 p(x) .6 3 .1 p(y) .7 3

> It seems reasonable to assume that more educated people will wait longer before having children. To determine whether this is reasonable draw a scatter diagram of years of education (EDUC) and the age at which a first child is born (AGEKDBRN). Describe y

> Do more educated people watch less television? Draw a scatter diagram of EDUC and TVHOURS. Describe what you have discovered.

> Use a graphical method to determine whether men and women differ with respect to working for themselves or someone else.

> Determine the quartiles of the amount of television watched (TVHOURS) by the respondents. Briefly describe what they tell you about this variable.

> Calculate the quartiles for the years of education (EDUC) completed by the respondents. What information do they provide?

> Find the quartiles of the respondents’ incomes (RINCOME). Describe what they tell you about incomes of the respondents.

> Do older people watch more television? Draw a scatter diagram of AGE and TVHOURS. What conclusion can you draw for the chart?

> If one half of a married couple works long hours, does the spouse work less? Draw a scatter diagram of HRS and SPHRS to answer the question.

> Refer to Exercise 3.73. Draw a scatter diagram of years of education (EDUC) and years of education of mothers (MAEDUC). What conclusion can you draw? Data from Exercise 3.73: Do more educated people have children who are also more educated? Answer this q

> Do more educated people have children who are also more educated? Answer this question by drawing a scatter diagram of the years of education (EDUC) and the years of education of his or her father (PAEDUC).

> The joint probability distribution of X and Y is shown in the following table. a. Determine the marginal distributions of X and Y . b. Compute the covariance and coefficient of correlation between X and Y . c. Develop the probability distribution of X +

> Do educated people tend to marry other educated people? Draw a scatter diagram of EDUC and SPEDUC. What conclusions can you draw from the graph?

> Use a pie chart to depict the proportion of respondents who worked for the government or worked in the private sector.

> Are there differences between men and women in terms of the completion of their highest degree? Use a graphical method to answer the question.

> Graphically describe the respondents’ highest completed degree.

> a. Determine the relative frequency distribution of marital status. b. Which graphical technique would you use to graphically describe marital status? c. Use your choice of graph.

> Graphically describe the racial makeup of the respondents.

> The population of the United States is approximately evenly divided between men and women. Draw a pie chart of the number of male and female respondents. Does it appear that the General Social Survey chose its respondents at random?

> Calculate the mean and standard deviation of the annual incomes (RINCOME). Assuming that the distribution of incomes is very skewed what information do the mean and standard deviation give you?

> Determine the mean and standard deviation of the amount of television watched (TVHOURS). If we assume that the distribution is bell shaped what do the two statistics tell you?

> Respondents were asked about the number of years of education (EDUC). Calculate the mean and standard deviation. Histograms of this variable reveal an approximate bell shape. What do the mean and standard deviation tell you?

> Refer to Exercise 7.49. a. Determine the distribution of X + Y . b. Determine the mean and variance of X + Y . c. Does your answer to part (b) equal the answer to Exercise 7.49? Data from Exercise 7.49: The bivariate distribution of X and Y is described

> Calculate the mean and standard deviation of the ages of the respondents. What do these statistics tell you?

> Calculate the mean and median of RINCOME. Is the mean greater than the median? If so, explain why.

> How much television were Americans watching in 2014? Answer the question by calculating the mean and median of TVHOURS. What have you learned?

> Calculate the mean and median of the years of education (EDUC). Briefly summarize what these statistics tell you about the years of education of Americans in 2014.

> Compute the mean and median of the ages (AGE) of the respondents. What information do these statistics give you?

> Do more educated (EDUC) Americans watch less television (TVHOURS)? a. To answer this question calculate a statistic that measures the strength of the linear relationship. b. Calculate the average marginal decrease in the hours of television viewing for e

> We would expect that people with more education would postpone having children. To examine the relationship between years of education (EDUC) and the age at which one’s first child is born (AGEKDBRN), perform a statistical analysis that answers the follo

> Use the Canada CPI Annual to calculate the inflation adjusted (using 2002 as the base) per capita debt from 1915 to 2015. Briefly describe your results.

> Use the population of Canada from 1870 to compute the per capita debt. Graph the results. What have you learned?

> The debt owed by the Canadian federal government was recorded for the years 1870 to 2015. Use a graph to present these figures. Should future tax-paying Canadians be concerned? Briefly explain.

> Refer to Exercise 7.49. Use the laws of expected value and variance of the sum of two variables to compute the mean and variance of X + Y . Data from Exercise 7.49: The bivariate distribution of X and Y is described here. y 1 2 1 .28 42 .12 .18 2.

> Use the U.S. CPI Annual to adjust the per capita debt figures to 1982–1984 dollars. Graph these figures. Does removing the effect of inflation allay your concerns for the future? Explain.

> Use the population of the United States from 1935 to 2015 to compute the per capita debt figures. Briefly describe what you have learned.

> The size of the U.S. federal government debt was recorded for every year starting in 1790. (Yes, the government was in debt even then.) Use a graphical technique to display these figures. Briefly describe what the graph tells you.

> Two other questions were asked in Exercise 2.65. Number of weeks job searching? Salary in ($ thousands)? a. Graphically describe salary. b. Is salary related to the number of weeks needed to land the job? Data from Exerices 2.65: A survey of the business

> In addition to the previously discussed data in Examples 3.3 and 3.4, the professor listed the midterm mark. Conduct an analysis of the relationship between the final exam mark and the midterm mark in each course. What does this analysis tell you?

> Examples 3.3 and 3.4 listed final marks in the business statistics course and the mathematical statistics course. The professor also provided the final marks in the first-year required calculus course. Graphically describe the relationship between calcul

> Several years ago the Barnes Exhibit toured major cities all over the world, with millions of people flocking to see it. Dr. Albert Barnes was a wealthy art collector who accumulated a large number of impressionist masterpieces; the total exceeds 800 pai

> Most car-rental companies keep their cars for about a year and then sell them to used car dealers. Suppose that one company decided to sell the used cars themselves. Because most used car buyers make their decision on what to buy and how much to spend ba

> Is airline travel becoming safer? To help answer this question, a statistics professor recorded the number of fatal accidents involving airliners carrying at least 19 passengers that occurred in the years 1950 to 2014. Use a graphical method to answer th

> Refer to Exercise 3.97. In addition to reporting the annual payment per director, the survey recorded the number of meetings last year. Use a graphical technique to summarize and present these data. Data from Exerices 3.97: Most publicly traded companies

> Refer to Exercise 7.49. Compute the covariance and the coefficient of correlation. Data from Exercise 7.49: The bivariate distribution of X and Y is described here. y 1 2 1 .28 42 .12 .18 2.

> Most publicly traded companies have boards of directors. The rate of pay varies considerably. A survey was undertaken by the Globe and Mail wherein 100 companies were surveyed and asked to report how much their directors were paid annually. Use a graphic

> An increasing number of consumers prefer to use debit cards in place of both cash and credit cards. To analyze the relationship between the amounts of purchases made with debit and credit cards, 240 people were interviewed and asked to report the amount

> Do better golfers play faster than poorer ones? To determine whether a relationship exists, a sample of 125 foursomes was selected. Their total scores and the amount of time taken to complete the round were recorded. Graphically depict the data and descr

> The monthly values of one British pound measured in American dollars since 1971 were recorded. Produce a graph that shows how the exchange rate has varied over the past 45 years.

> When the Dow-Jones Industrial Index increases it usually means that the economy is growing, which in turn usually means that the unemployment rate is low. A statistics professor pointed out that in numerous periods (including when this edition was being

> In Chapters 16, 17, and 18, we introduce regression analysis, which addresses the relationships among variables. One of the first applications of regression analysis was to analyze the relationship between the heights of fathers and sons. Suppose that in

> SPAM is an unfortunate fact of life. A random sample of university students was asked to report the number of Spam e-mails they receive in a typical day. Use an appropriate graphical method to display these data.

> An economist wanted to determine whether a relationship existed between interest rates and currencies (measured in U.S. dollars). He recorded the monthly interest rate and the currency indexes for the years 1982 to 2008. Graph the data and describe the r

> Studies of twins may reveal more about the “nature” or “nurture” debate. The issue being debated is whether nature or the environment has more effect on individual traits such as intelligence. Suppose that a sample of identical twins was selected and the

> The bivariate distribution of X and Y is described here. a. Find the marginal probability distribution of X. b. Find the marginal probability distribution of Y . c. Compute the mean and variance of X. d. Compute the mean and variance of Y . y 1 2 1

> The monthly exchange rate of U.S. dollars to one Australian dollar was recorded from 1971 to 2016. Draw a graph that shows how the exchange rate has varied over the past 41 years.

> Gold and precious metals have traditionally been considered a hedge against inflation. If this is true, we would expect that a fund made up of precious metals (gold, silver, platinum, and others) would have a strong positive relationship with the inflati

> A survey of the business school graduates undertaken by a university placement office asked, among other questions, in which area each person was employed. The areas of employment are as follows: 1. Accounting 2. Finance 3. General management 4. Marketin

> The Red Lobster Restaurant chain conducts regular surveys of its customers 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), Fair

> There are several ways to teach applied statistics. The most popular approaches are as follows: 1. Emphasize manual calculations. 2. Use a computer combined with manual calculations. 3. Use a computer exclusively with no manual calculations. A survey of

> A sample of 200 people who had purchased food at the concession stand at Yankee Stadium was asked to rate the quality of the food. The responses are as follows: 1. Poor 2. Fair 3. Good 4. Very good 5. Excellent Draw a graph that describes the data. What

> The Wilfrid Laurier University bookstore conducts annual surveys of its customers. One question asks respondents to rate the prices of textbooks. The wording is, “The bookstore’s prices of textbooks are reasonable.” The responses are as follows: 1. Stro

> Refer to Exercise 2.59. The percentage of uninsured in 2013 and 2014 in each of the 50 states plus District of Columbia was recorded. Use a graphical technique to show the decrease in the uninsured rate. Data from Exercise 2.59: The primary objective of

> The primary objective of the Affordable Care Act was to decrease the number of nonelderly without any health insurance. It is estimated that there are still approximately 40 million Americans without health insurance. Researchers asked a sample of them w

> The Consumer Expenditure Survey measures how consumers allocate their spending. A recent survey asked respondents to specify the amount of their budget spent on food, housing, transportation, healthcare, and insurance and pensions. Also recorded were the

> Refer to Exercise 7.45. a. Determine the distribution of X + Y . b. Determine the mean and variance of X + Y . c. Does your answer to part (b) equal the answer to Exercise 7.45? Data from Exercise 7.45: The following table lists the bivariate distributio

> June 7 is known as Tax Freedom day in Canada. The annual taxes paid by an average Canadian family earning $105,236 is $45,167. The breakdown of these taxes is shown in the table below. Use an appropriate graphical technique to present these figures. Inco

> 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

> 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

> Your favorite team is in the final playoffs. You have assigned a probability of 60% that it will win the championship. Past records indicate that when teams win the championship, they win the first game of the series 70% of the time. When they lose the s

> Three airlines serve a small town in Ohio. Airline A has 50% of all the scheduled flights, airline B has 30%, and airline C has the remaining 20%. Their on-time rates are 80%, 65%, and 40%, respectively. A plane has just left on time. What is the probabi

> Data from the Office on Smoking and Health, Centers for Disease Control and Prevention, indicate that 40% of adults who did not finish high school, 34% of high school graduates, 24% of adults who completed some college, and 14% of college graduates smoke

> Refer to Exercise 6.93. If 40% of the people in a community will have a heart attack, what is the probability that a person with periodontal disease will have a heart attack? Data from Exercise 6.93: Bad gums may mean a bad heart. Researchers discovered

> The U.S. National Highway Traffic Safety Administration gathers data concerning the causes of highway crashes where at least one fatality has occurred. The following probabilities were determined from the 1998 annual study (BAC is blood-alcohol content).

> Refer to Exercise 6.70. The plant manager randomly selects a molding from the early morning run and discovers it is defective. What is the probability that the foreman forgot to shut off the machine the previous night? Data from Exercise 6.70: A foreman

> Three contractors (call them contractors 1, 2, and 3) bid on a project to build a new bridge. What is the sample space?

> Refer to Exercise 7.45. Use the laws of expected value and variance of the sum of two variables to compute the mean and variance of X + Y . Data from Exercise 7.45: The following table lists the bivariate distribution of X and Y . y 1 2 1 5 .1 .1 3 2

> Refer to Example 6.9. An MBA applicant believes that the probability of scoring more than 650 on the GMAT without the preparatory course is .95. What is the probability of attaining that level after taking the preparatory course? Data from Exercise 6.9:

> Refer to Exercise 6.60. Find the following. a. P(A 0 B) b. P(AC 0 B) c. P(A 0 BC ) d. P(AC 0 BC ) Data from Exercise 6.60: Determine all joint probabilities from the following. P(A) = .8 P(B 0 A) = .4 P(AC ) = .2 P(B 0 AC ) = .7

> Refer to Exercise 6.59. Determine P(A 0 B). Data from Exercise 6.59: Given the following probabilities, compute all joint probabilities. P(A) = .9 P(B 0 A) = .4 P(AC ) = .1 P(B 0 AC ) = .7

> A statistics professor was in the process of comparing the pass rates (the percentage of entering students who graduate in 5 years or less) for B.A.’s, B.B.A.’s, B.Sc.’s, and B.Eng.’

> How many Americans under the age of 40 have student debts? A Pew Research Center attempted to answer the question by asking whether respondents had student debt and in what was their occupation. The following probabilities were determined. Calculate the

> A financial analyst estimates that the probability that the economy will experience a recession in the next 12 months is 25%. She also believes that if the economy encounters a recession, the probability that her mutual fund will increase in value is 20%

> According to TNS Intersearch, 69% of wireless web users use it primarily for receiving and sending e-mail. Suppose that three wireless web users are selected at random. What is the probability that all of them use it primarily for e-mail?

> The controls of an airplane have several backup systems or redundancies so that if one fails the plane will continue to operate. Suppose that the mechanism that controls the flaps has two backups. If the probability that the main control fails is .0001 a

> The manager of a computer store has kept track of the number of computers sold per day. On the basis of this information, the manager produced the following list of the number of daily sales. Number of Computers Sold

> An investor believes that on a day when the Dow Jones Industrial Average (DJIA) increases, the probability that the NASDAQ also increases is 77%. If the investor believes that there is a 60% probability that the DJIA will increase tomorrow, what is the p

> Refer to Exercise 7.45. Compute the covariance and the coefficient of correlation. Data from Exercise 7.45: The following table lists the bivariate distribution of X and Y . y 1 2 1 5 .1 .1 3 2.

> A financial analyst has determined that there is a 22% probability that a mutual fund will outperform the market over a 1-year period provided that it outperformed the market the previous year. If only 15% of mutual funds outperform the market during any

> All printed circuit boards (PCBs) that are manufactured at a certain plant are inspected. An analysis of the company’s records indicates that 22% are flawed in some way. Of those that are flawed, 84% are reparable and the rest must be discarded. If a new

> The Nickels restaurant chain regularly conducts surveys of its customers. Respondents are asked to assess food quality, service, and price. The responses are Excellent Good Fair Surveyed customers are also asked whether they would come back. After ana

> The chartered financial analyst (CFA) is a designation earned after a candidate has taken three annual exams (CFA I, II, and III). The exams are taken in early June. Candidates who pass an exam are eligible to take the exam for the next level in the foll

> A survey of middle-aged men reveals that 28% of them are balding at the crown of their heads. Moreover, it is known that such men have an 18% probability of suffering a heart attack in the next 10 years. Men who are not balding in this way have an 11% pr

> Among many other pieces of information, the U.S. Census Bureau records the race or ethnicity of the residents of every county in every state. From these results, the bureau calculated a “diversity index” that measures the probability that two people chos

> A study undertaken by the Miami-Dade Supervisor of Elections revealed that 44% of registered voters are Democrats, 37% are Republicans, and 19% are others. If two registered voters are selected at random, what is the probability that both of them have th

> A foreman for an injection-molding firm admits that on 10% of his shifts, he forgets to shut off the injection machine on his line. This causes the machine to overheat, increasing the probability from 2% to 20% that a defective molding will be produced d

> Refer to Exercise 6.6. Employing the subjective approach a political scientist has assigned the following probabilities: P(Adams wins) = .42 P(Brown wins) = .09 P(Collins wins) = .27 P(Dalton wins) = .22 Determine the probabilities of the following event

> A telemarketer calls people and tries to sell them a subscription to a daily newspaper. On 20% of her calls, there is no answer or the line is busy. She sells subscriptions to 5% of the remaining calls. For what proportion of calls does she make a sale?