Question: For many restaurants, the amount of time

> 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

> Shoppers can pay for their purchases with cash, a credit card, or a debit card. Suppose that the proprietor of a shop determines that 60% of her customers use a credit card, 30% pay with cash, and the rest use a debit card. a. Determine the sample space

> The following table lists the joint probabilities of achieving grades of A and not achieving A’s in two MBA courses. a. What is the probability that a student achieves a grade of A in marketing? b. What is the probability that a studen

> Refer to Exercise 7.32. The cost of parking is $2.50 per hour. Calculate the mean and standard deviation of the amount of revenue each car generates. Data from Exercise 7.32: When parking a car in a downtown parking lot, drivers pay according to the numb

> Refer to Exercise 6.83. A respondent who said that the U.K. leaving the EU is a bad thing was selected. What is the probability that the respondent is from Italy? Data from Exercise 6.83: In June 2016, Britons were heading to the polls to vote in a refer

> What are the sensitivity, specificity, positive predictive value, and negative predictive value in the previous exercise?

> Refer to Exercise 6.9. Suppose that you believe that contractor 1 is twice as likely to win as contractor 3 and that contractor 2 is three times as likely to win as contactor 3. What are the probabilities of winning for each contractor? Data from Exercis

> The weather forecaster reports that the probability of rain tomorrow is 10%. a. Which approach was used to arrive at this number? b. How do you interpret the probability?

> Carbon monoxide (CO) in the home is caused by faulty furnaces burning natural gas or heating oil. Concentrations above 35 parts per million (ppm) is considered dangerous. Suppose that a municipal home inspector randomly samples 180 houses around the city

> A professional income tax preparer recorded the amount of tax rebate and the total taxable amount of a sample of 80 customers. Compute whichever statistics you need to determine whether tax rebates increase as the taxable income increases.

> To determine the relationship between age of cars and annual repair costs a random sample of car owners was drawn and the two variables were recorded. Calculate statistics to determine whether cost of repairs increase as the car ages and on average what

> Refer to Exercise 4.95. In another survey by the Bureau of Labor Statistics respondents who reported that they rent their dwelling were asked their age and how much they spend annually on rent. Use a statistical analysis to determine whether the data ind

> The U.S. Census Bureau in conjunction with the Bureau of Labor Statistics conducts surveys that record a wide variety of subjects. In the Consumer Expenditure Survey of 2014–2015 respondents were asked their age and the amount of money spent in the previ

> A manufacturer has recorded its cost of electricity and the total number of hours of machine time for each of 52 weeks. Estimate the fixed and variable electricity costs.

> When parking a car in a downtown parking lot, drivers pay according to the number of hours or parts thereof. The probability distribution of the number of hours cars are parked has been estimated as follows. Find the mean and standard deviation of the n

> A manufacturing firm produces its products in batches using sophisticated machines and equipment. The general manager wanted to investigate the relationship between direct labor costs and the number of units produced per batch. He recorded the data from

> One way of measuring the extent of unemployment is through the help wanted index, which measures the number of want ads in the nation’s newspapers. The higher the index, the greater is the demand for workers. Another measure is the unemployment rate amon

> When the price of crude oil increases, do oil companies drill more oil wells? To determine the strength and nature of the relationship, an economist recorded the price of a barrel of domestic crude oil (West Texas crude) and the number of exploratory oil

> A real estate developer of single-family dwellings across the country is in the process of developing plans for the next several years. An analyst for the company believes that interest rates are likely to increase but remain at low levels. To to build,

> A regular feature in a newspaper asks readers to respond via e-mail to a survey that requires a yes or no response. In the following day’s newspaper, the percentage of yes and no responses are reported.Discuss why we should ignore these statistics.

> All Canadians have government-funded health insurance, which pays for any medical care they require. However, when traveling out of the country, Canadians usually acquire supplementary health insurance to cover the difference between the costs incurred f

> The unemployment rate is an important measure of a country’s economic health. The unemployment rate measures the percentage of people who are looking for work and who are without jobs. Unfortunately, it can be a misleading statistic bec

> Students who apply to MBA programs must take the Graduate Management Admission Test (GMAT). University admissions committees use the GMAT score as one of the critical indicators of how well a student is likely to perform in the MBA program. However, the

> Are the marks one receives in a course related to the amount of time spent studying the subject? To investigate this mysterious possibility, a student took a random sample of 10 students who had enrolled in an accounting class last semester. He asked eac

> A retailer wanted to estimate the monthly fixed and variable selling expenses. As a first step, she collected data from the past 8 months. The total selling expenses ($1,000) and the total sales ($1,000) were recorded and are listed below. Total Sales

> Refer to Exercise 7.30. Suppose that, on average, customers spend 10 minutes in each store they enter. Find the mean and standard deviation of the total amount of time customers spend in stores. Data from Exercise 7.30: A shopping mall estimates the prob

> Refer to Exercise 4.83. You’ve now learned that the two sample standard deviations are 16 and 12. a. Calculate the coefficient of correlation. What does this statistic tell you about the relationship between the two variables? b. Calculate the coefficie

> The covariance of two variables has been calculated to be −150. What does the statistic tell you about the two variables?

> To determine premiums for automobile insurance, companies must have an understanding of the variables that affect whether a driver will have an accident. The age of the driver may top the list of variables. The following table lists the number of drivers

> For each of the following examples of data, determine the type. a. The number of miles joggers run per week b. The starting salaries of graduates of MBA programs c. The months in which a firm’s employees choose to take their vacations d. The final letter

> The production of steel has often been used as a measure of the economic strength of a country. The next table lists the steel produced in the 20 largest steel-producing nations in 2014. The units are millions of metric tons. Use a graphical technique to

> a. What is meant by self-selected sample? b. Give an example of a recent poll that involved a self-selected sample. c. Why are self-selected samples not desirable?

> The planet may be threatened by global warming/climate change, possibly caused by burning fossil fuels (petroleum, natural gas, and coal) that produced carbon dioxide (CO2). The following table lists the top 15 producers of CO2 and the annual amounts (in

> The table below lists the electricity consumption (in Kilowatt-hours) in the top 20 electricity using countries. Graph the numbers to help describe the figures. Country Electricity Consumption (Kilowatt-Hours) Australia

> There are 42 gallons in a barrel of oil. The number of products produced and the proportion of the total are listed in the following table. Draw a graph to depict these numbers. Product Proportion Gasoline

> A random sample of households was selected. Each was asked how much they spent in food away from home (restaurants, fast food, etc.) last year. Calculate the quartiles and describe what information you’ve extracted from them.

> A shopping mall estimates the probability distribution of the number of stores mall customers actually enter, as shown in the table. Find the mean and standard deviation of the number of stores entered. 1 2 3 4 5 6 P(x) .04 .19 .22 28 .12 .09 .06

> In the United States, taxpayers are allowed to deduct mortgage interest from their incomes before calculating the amount of income tax they are required to pay. The Internal Revenue Service sampled 500 tax returns that had a mortgage interest deduction a

> Do golfers who are members of private courses play faster than players on a public course? The amount of time taken for a sample of privatecourse and public-course golfers was recorded. Find the quartiles for each group and describe what you have learned

> A random sample of Boston Marathon runners was drawn and the times to complete the race were recorded. Determine the quartiles and briefly describe what they tell you.

> The career-counseling center at a university wanted to learn more about the starting salaries of the university’s graduates. They asked each graduate to report the highest salary offer received. The survey also asked each graduate to report the degree an

> The Travel Industry Association of America sponsored a poll that asked a random sample of people how much they spent in preparation for pleasure travel. Determine the quartiles and describe what they tell you.

> a. Describe why the Literary Digest poll of 1936 has become infamous. b. What caused this poll to be so wrong?

> How much do pets cost? A random sample of dog and cat owners was asked to compute the amounts of money spent on their pets (exclusive of pet food). Determine the quartiles and describe your findings.

> Accountemps, a company that supplies temporary workers, sponsored a survey of 100 executives. Each was asked to report the number of minutes they spend screening each job resume they receive. a. Compute the quartiles. b. What information did you derive f

> Many automotive experts believe that speed limits on highways are too low. One particular expert has stated that he thinks that most drivers drive at speeds that they consider safe. He suggested that the “correct” speed limit should be set at the 85th pe

> The natural remedy Echinacea is reputed to boost the immune system, which will reduce the number of flu and colds. A 6-month study was undertaken to determine whether the remedy works. From this study, the following probability distribution of the number

> Find the interquartile range of the following sample. 9 28 15 21 12 22 29 20 23 31 11 19 24 16 13

> Compute the interquartile range from the following data. 5 8 14 6 21 11 9 10 18 2

> Refer to Exercise 4.62. Determine the interquartile range. Data from Exercise 4.62: Calculate the 3rd and 6th deciles of the accompanying data. 7 18 12 17 29 18 4 27 30 2 4 10 21 5 8

> Refer to Exercise 4.61. Determine the interquartile range. Data from Exercise 4.61: Determine the first, second, and third quartiles of the following data. 10.5 14.7 15.3 17.7 15.9 12.2 10.0 14.1 13.9 18.5 13.9 15.1 14.7

> Calculate the 3rd and 6th deciles of the accompanying data. 7 18 12 17 29 18 4 27 30 2 4 10 21 5 8

> Determine the first, second, and third quartiles of the following data. 10.5 14.7 15.3 17.7 15.9 12.2 10.0 14.1 13.9 18.5 13.9 15.1 14.7

> Find the first and second quintiles (20th and 40th percentiles) of the data shown here. 52 61 88 43 64 71 39 73 51 60

> For each of the following sampling plans, indicate why the target population and the sampled population are not the same. a. To determine the opinions and attitudes of customers who regularly shop at a particular mall, a surveyor stands outside a large d

> Find the third and eighth deciles (30th and 80th percentiles) of the following data set. 26 23 29 31 24 22 15 31 30 20

> Calculate the first, second, and third quartiles of the following sample. 5 8 2 9 5 3 7 4 2 7 4 10 4 3 5

> After analyzing the frequency with which cross-country skiers participate in their sport, a sportswriter created the following probability distribution for X = number of times per year cross-country skiers ski. Find the following. a. P(3) b. P(X â

> Determine the first, second, and third quartiles of the data shown next. 2 4 6 8 10 12 14 16 18 20

> Black Friday in the United States is the day after Thanksgiving. Many retailers offer doorcrasher specials to induce customers to shop at their stores. The number of door-crasher specials is limited. However, the sale price is so low that people who want

> Refer to Exercise 3.54. Use the U.S. CPI monthly file to measure the Dow Jones Industrial Average in 1982–1984 constant dollars. What have you learned? Data from Exercise 3.54: The Jones Industrial Average was recorded monthly (close) from 1950 to 2016.

> The Jones Industrial Average was recorded monthly (close) from 1950 to 2016. Use a graph to describe these numbers.

> The exchange rate of the Japanese Yen to one U.S. dollar was recorded monthly for the period 1971 to 2016. Draw a graph of these figures and interpret your findings.

> The exchange rate of the Canadian dollar to one U.S. dollar was recorded monthly for the period 1971 to 2016. Draw a graph of these figures and interpret your findings.

> The monthly value of U.S. exports to China (in $millions) and imports from China from 1985 to 2016 was recorded. a. Draw a line chart of U.S. exports to China. b. Draw a line chart of U.S. imports from China. c. Calculate the trade balance and draw a lin

> The monthly value of U.S. exports to Japan (in $millions) and imports from Japan from 1985 to 2016 was recorded. a. Draw a line chart of U.S. exports to Japan. b. Draw a line chart of U.S. imports from Japan. c. Calculate the trade balance and draw a lin

> List five important points to consider when designing a questionnaire.

> The monthly value of U.S. exports to Canada (in $millions) and imports from Canada from 1985 to 2016 was recorded. a. Draw a line chart of U.S. exports to Canada. b. Draw a line chart of U.S. imports from Canada. c. Calculate the trade balance and draw a

> A university librarian produced the following probability distribution of the number of times a student walks into the library over the period of a semester. Find the following probabilities. a. P(X ≥ 20) b. P(X = 60) c. P(X > 50) d.

> A sample of households was asked to report the amount of money they spend annually for fruits and vegetables. Compute the mean and standard deviation of these data. What do these statistics tell you about the distribution of the amounts?

> A random sample of homeowners was asked to report the amount of money they paid in property taxes last year. Compute the mean and standard deviation. Assuming that the amounts are highly positively skewed describe what the two statistics tell you.

> An amateur golf kept track of the scores of her last 100 rounds. Calculate the mean and standard deviation. Assuming that the distribution of scores is extremely skewed interpret the mean and standard deviation.

> Flight delays in airplane travel is a fact of life for travelers. Suppose that the time for each of a sample of 125 delays in arriving (in minutes) was recorded. Early arrivals are shown as negative numbers and on-time arrivals are represented by zeroes.

> Everyone is familiar with waiting lines or queues. For example, people wait in line at a supermarket to go through the checkout counter. There are two factors that determine how long the queue becomes. One is the speed of service. The other is the number

> To learn more about the size of withdrawals at a banking machine, the proprietor took a sample of 75 withdrawals and recorded the amounts. Determine the mean and standard deviation of these data, and describe what these two statistics tell you about the

> Variance is often used to measure the quality in production-line products. Suppose that a sample of steel rods that are supposed to be exactly 100 cm long is taken. The length of each is determined, and the results are recorded. Calculate the variance an

> Three men are trying to make the football team as punters. The coach had each of them punt the ball 50 times, and the distances were recorded. a. Compute the variance and standard deviation for each punter. b. What do these statistics tell you about the

> Many traffic experts argue that the most important factor in accidents is not the average speed of cars but the amount of variation. Suppose that the speeds of a sample of 200 cars were taken over a stretch of highway that has seen numerous accidents. Co

> a. List three methods of conducting a survey of people. b. Give an important advantage and disadvantage of each of the methods listed in part (a).

> A survey of Amazon.com shoppers reveals the following probability distribution of the number of books purchased per hit. a. What is the probability that an Amazon.com visitor will buy four books? b. What is the probability that an Amazon.com visitor wil

> There has been much media coverage of the high cost of medicinal drugs in the United States. One concern is the large variation from pharmacy to pharmacy. To investigate, a consumer advocacy group took a random sample of 100 pharmacies around the country

> A statistics practitioner determined that the mean and standard deviation of a data set were 120 and 30, respectively. What can you say about the proportions of observations that lie between each of the following intervals? a. 90 and 150 b. 60 and 180 c.

> A set of data whose histogram is extremely skewed yields a mean and standard deviation of 70 and 12, respectively. What is the minimum proportion of observations that a. are between 46 and 94? b. are between 34 and 106?

> Refer to Exercise 4.35. Approximately what proportion of observations a. are less than 46? b. are less than 58? c. are greater than 54? Data from Exercise 4.35: A set of data whose histogram is bell shaped yields a mean and standard deviation of 50 and 4

> A set of data whose histogram is bell shaped yields a mean and standard deviation of 50 and 4, respectively. Approximately what proportion of observations a. are between 46 and 54? b. are between 42 and 58? c. are between 38 and 62?

> Create a sample of five observations whose mean is 6 and whose standard deviation is 0.

> A friend calculates a variance and reports that it is –25.0. How do you know that he has made a calculation error?

> Refer to Exercise 4.31. Calculate the variance for each part. Was your answer in Exercise 4.31 correct? Data from Exercise 4.31: a. 17 b. 22 29 12 16 11 18 23 20 17 C. 24 37 6. 39 29

> Examine the three samples listed here. Without performing any calculations, indicate which sample has the largest amount of variation and which sample has the smallest amount of variation. Explain how you produced your answer. a. 17 b. 22 29 12 16 11