The Pew American Trends Survey includes a series of questions on attitudes toward automation. The May 2018 results showed that 2977 of 4135 respondents are worried about a future in which robots and computers can do many human jobs, 2770 are worried about the development of algorithms that can evaluate and hire job candidates, and 2233 are worried about the development of driverless vehicles. a. Develop a point estimate of the proportion of respondents who are worried about a future in which robots and computers can do many human jobs. b. Develop a point estimate of the proportion of respondents who are worried about the development of algorithms that can evaluate and hire job candidates. c. Develop a point estimate of the proportion of respondents who are worried about the development of driverless vehicles.
> Data showing the population by state in millions of people follow (The World Almanac). a. Develop a frequency distribution, a percent frequency distribution, and a histogram. Use a class width of 2.5 million. b. Does there appear to be any skewness in
> The file MedianHousehold contains the median household income for a family with two earners for each of the fifty states (American Community Survey). a. Construct a frequency and a percent frequency distribution of median household income. Begin the firs
> The SAT is a standardized test used by many colleges and universities in their admission decisions. More than one million high school students take the SAT each year. The current version of the SAT includes three parts: reading comprehension, mathematics
> The Panama Railroad Company was established in 1850 to construct a railroad across the isthmus that would allow fast and easy access between the Atlantic and Pacific Oceans. The following table provides annual returns for Panama Railroad stock from 1853
> Automobiles traveling on a road with a posted speed limit of 55 miles per hour are checked for speed by a state police radar system. Following is a frequency distribution of speeds. a. What is the mean speed of the automobiles traveling on this road? b
> Does a major league baseball team’s record during spring training indicate how the team will play during the regular season? Over a six-year period, the correlation coefficient between a team’s winning percentage in sp
> Travel + Leisure magazine provides an annual list of the 500 best hotels in the world. The magazine provides a rating for each hotel along with a brief description that includes the size of the hotel, amenities, and the cost per night for a double room.
> The data contained in the file FoodIndustry show the company/chain name, the average sales per store ($1000s), and the food segment industry for 47 restaurant chains (Quick Service Restaurant Magazine website). a. What was the mean U.S. sales per store f
> Revenue of World’s Most Valuable Brands. Refer to Table 2.12. a. Prepare a crosstabulation of the data on Industry (rows) and Brand Revenue ($ billions). Use class intervals of 25 starting at 0 for Brand Revenue ($ billions). b. Prepa
> The following data represent a sample of 14 household incomes ($1000s). Answer the following questions based on this sample. a. What is the median household income for these sample data? b. According to a previous survey, the median annual household in
> Public transportation and the automobile are two methods an employee can use to get to work each day. Samples of times recorded for each method are shown. Times are in minutes. a. Compute the sample mean time to get to work for each method. b. Compute
> Smartphones have become ubiquitous for most people and have become the predominant means of communication among people. Consider the following data indicating the number of minutes in a month spent interacting with others via a smartphone for a sample of
> The average waiting time for a patient at an El Paso physician’s office is just over 29 minutes, well above the national average of 21 minutes. In order to address the issue of long patient wait times, some physician’s
> A 2017 USA Today article reports that NCAA football coaches’ salaries have continued to increase in recent years (USA Today). The annual base salaries for the previous head football coach and the new head football coach at 23 schools are given in the fil
> Americans tend to dine out multiple times per week. The number of times a sample of 20 families dined out last week provides the following data. a. Compute the mean and median. b. Compute the first and third quartiles. c. Compute the range and interquar
> A zoo has categorized its visitors into three categories: member, school, and general. The member category refers to visitors who pay an annual fee to support the zoo. Members receive certain benefits such as discounts on merchandise and trips planned by
> Electric plug-in vehicle sales have been increasing worldwide. The table below displays data collected by the U.S. Department of Energy on electric plug-in vehicle sales in the words top markets in 2013 and 2015. (Data compiled by Argonne National Labora
> Colleges’ Year Founded and Percent Graduated. Refer to the data set in Table 2.18. a. Construct a crosstabulation with Year Founded as the row variable and % Graduate as the column variable. Use classes starting with 1600 and ending w
> Table 2.18 shows a portion of the data for a sample of 103 private colleges and universities. The complete data set is contained in the file Colleges. The data include the name of the college or university, the year the institution was founded, the tuiti
> Each year Forbes ranks the world’s most valuable brands. A portion of the data for 82 of the brands in the 2013 Forbes list is shown in Table 2.12 (Forbes website). The data set includes the following variables: Brand: The name of the b
> Fortune magazine publishes an annual survey of the 100 best companies to work for. The data in the file FortuneBest100 shows the rank, company name, the size of the company, and the percentage job growth for full-time employees for 98 of the Fortune 100
> Western University has only one women’s softball scholarship remaining for the coming year. The final two players that Western is considering are Allison Fealey and Emily Janson. The coaching staff has concluded that the speed and defen
> The U.S. Census Bureau serves as the leading source of quantitative data about the nation’s people and economy. The following crosstabulation shows the number of households (1000s) and the household income by the level of education for
> The term “beta” refers to a measure of a stock’s price volatility relative to the stock market as a whole. A beta of 1 means the stock’s price moves exactly with the market. A beta o
> Colleges’ Year Founded and Cost. Refer to the data set in Table 2.18. a. Construct a scatter diagram to show the relationship between Year Founded and Tuition & Fees. b. Comment on any relationship between the variables.
> According to the Wall Street Journal, a startup company’s ability to gain funding is a key to success. The funds raised (in millions of dollars) by 50 startup companies appear below. a. Construct a stem-and-leaf display. b. Comment on
> The days to maturity for a sample of five money market funds are shown here. The dollar amounts invested in the funds are provided. Use the weighted mean to determine the mean number of days to maturity for dollars invested in these five money market fun
> In 2014, the 32 teams in the National Football League (NFL) were worth, on average, $1.17 billion, 5% more than in 2013. The following data show the annual revenue ($ millions) and the estimated team value ($ millions) for the 32 NFL teams in 2014 (Forbe
> U.S. companies lose $63.2 billion per year from workers with insomnia. Accordign to a 2013 article in the Wall Street Journal, workers lose an average of 7.8 days of productivity per year due to lack of sleep. The following data show the number of hours
> Colleges’ Cost and Percent Graduated. Refer to the data set in Table 2.18. a. Prepare a scatter diagram to show the relationship between Tuition & Fees and % Graduate. b. Comment on any relationship between the variables.
> The following crosstabulation shows the number of households (1000s) in each of the four regions of the United States and the number of households at each income level (U.S. Census Bureau website, https://www.census .gov/data/tables/time-series/demo/inco
> Many service companies collect data via a follow- up survey of their customers. For example, to ascertain customer sentiment, Delta Air Lines sends an email to customers immediately following a flight. Among other questions, Delta asks: How likely are yo
> J.D. Power and Associates surveys new automobile owners to learn about the quality of recently purchased vehicles. The following questions were asked in a J.D. Power Initial Quality Survey. a. Did you purchase or lease the vehicle? b. What price did you
> Summarizing Phone Data. Refer to the data set in Table 1.7. a. What is the average price for the phones? b. What is the average talk time for the phones? c. What percentage of the phones have a voice quality of excellent?
> In a recent report, the top five most-visited English-language websites were google.com (GOOG), facebook.com (FB), youtube.com (YT), yahoo. com (YAH), and wikipedia.com (WIKI). The most-visited websites for a sample of 50 Internet users are shown in the
> A questionnaire provides 58 Yes, 42 No, and 20 no-opinion answers. a. In the construction of a pie chart, how many degrees would be in the section of the pie showing the Yes answers? b. How many degrees would be in the section of the pie showing the No a
> A partial relative frequency distribution is given. a. What is the relative frequency of class D? b. The total sample size is 200. What is the frequency of class D? c. Show the frequency distribution. d. Show the percent frequency distribution.
> Discuss the differences between statistics as numerical facts and statistics as a discipline or field of study.
> The Wall Street Journal provides the net asset value, the year-to-date percent return, and the three-year percent return for 882 mutual funds at the end of 2017. Assume that a simple random sample of 12 of the 882 mutual funds will be selected for a foll
> The following stocks make up the Dow Jones Industrial Average. Suppose you would like to select a sample of six of these companies to conduct an indepth study of management practices. Use the first two digits in each row of the ninth column of Table 7.1
> The County and City Data Book, published by the Census Bureau, lists information on 3139 counties throughout the United States. Assume that a national study will collect data from 30 randomly selected counties. Use four-digit random numbers from the last
> Recently, management at Oak Tree Golf Course received a few complaints about the condition of the greens. Several players complained that the greens are too fast. Rather than react to the comments of just a few, the Golf Association conducted a survey of
> A student government organization is interested in estimating the proportion of students who favor a mandatory “pass-fail” grading policy for elective courses. A list of names and addresses of the 645 students enrolled
> Assume that the population proportion is .44. Compute the standard error of the proportion, , for sample sizes of 500,000; 1,000,000; 5,000,000; 10,000,000; and 100,000,000. What can you say about the size of the standard error of the sample proportion
> The 10 most active stocks on the New York Stock Exchange for a given week, are shown here. Exchange authorities decided to investigate trading practices using a sample of three of these stocks. a. Beginning with the first random digit in column 6 of Tab
> Assume that the population proportion is .55. Compute the standard error of the proportion, , for sample sizes of 100, 200, 500, and 1000. What can you say about the size of the standard error of the proportion as the sample size is increased?
> A sample of size 100 is selected from a population with / = .40. a. What is the expected value of /? b. What is the standard error of /? c. Show the sampling distribution of /. d. What does the sampling distribution of / show?
> Fortune publishes data on sales, profits, assets, stockholders’ equity, market value, and earnings per share for the 500 largest U.S. industrial corporations every year. Assume that you want to select a simple random sample of 10 corpor
> Assume the population standard deviation is s = 25. Compute the standard error of the mean, sx, for sample sizes of 50, 100, 150, and 200. What can you say about the size of the standard error of the mean as the sample size is increased?
> According to Wine-Searcher, wine critics generally use a wine-scoring scale to communicate their opinions on the relative quality of wines. Wine scores range from 0 to 100, with a score of 95–100 indicating a great wine, 90â€
> Morningstar publishes ratings data on 1208 company stocks. A sample of 40 of these stocks is contained in the file Morningstar. Use the Morningstar data set to answer the following questions. a. Develop a point estimate of the proportion of the stocks th
> The following crosstabulation shows the average speed of the 25 winners by year of the Daytona 500 automobile race (The World Almanac). a. Calculate the row percentages. b. What is the apparent relationship between average winning speed and year? What
> Tablet PCs: Cost, CPU, and Operating System. Refer to Table 1.6. a. What is the average cost for the tablets? b. Compare the average cost of tablets with a Windows operating system to the average cost of tablets with an Android operating system. c. Wha
> A sample of 5 months of sales data provided the following information: a. Develop a point estimate of the population mean number of units sold per month. b. Develop a point estimate of the population standard deviation.
> A survey question for a sample of 150 individuals yielded 75 Yes responses, 55 No responses, and 20 No Opinions. a. What is the point estimate of the proportion in the population who respond Yes? b. What is the point estimate of the proportion in the pop
> The following data are from a simple random sample. 5 8 10 7 10 14 a. What is the point estimate of the population mean? b. What is the point estimate of the population standard deviation?
> Using Figure 6.6 as a guide, sketch a normal curve for a random variable x that has a mean of m = 100 and a standard deviation of s = 10. Label the horizontal axis with values of 70, 80, 90, 100, 110, 120, and 130.
> The electric-vehicle manufacturing company Tesla estimates that a driver who commutes 50 miles per day in a Model S will require a nightly charge time of around 1 hour and 45 minutes (105 minutes) to recharge the vehicle’s battery (Tesla company website)
> Delta Airlines quotes a flight time of 2 hours, 5 minutes for its flights from Cincinnati to Tampa. Suppose we believe that actual flight times are uniformly distributed between 2 hours and 2 hours, 20 minutes. a. Show the graph of the probability densit
> A person must score in the upper 2% of the population on an IQ test to qualify for membership in Mensa, the international high-IQ society. If IQ scores are normally distributed with a mean of 100 and a standard deviation of 15, what score must a person h
> The random variable x is known to be uniformly distributed between 10 and 20. a. Show the graph of the probability density function. b. Compute P(x < 15). c. Compute P(12 ≤ x ≤ 18). d. Compute E(x). e. Compute Var(x).
> Draw a graph for the standard normal distribution. Label the horizontal axis at values of −3, −2, −1, 0, 1, 2, and 3. Then use the table of probabilities for the standard normal distribution inside the front cover of the text to compute the following pro
> The random variable x is known to be uniformly distributed between 1.0 and 1.5. a. Show the graph of the probability density function. b. Compute P(x = 1.25). c. Compute P(1.0 ≤ x ≤ 1.25). d. Compute P(1.20 < x < 1.5).
> The Daytona 500 is a 500-mile automobile race held annually at the Daytona International Speedway in Daytona Beach, Florida. The following crosstabulation shows the automobile make by average speed of the 25 winners over a 25 year period (The World Alman
> Employee retention is a major concern for many companies. A survey of Americans asked how long they have worked for their current employer (Bureau of Labor Statistics website). Consider the following example of sample data of 2000 college graduates who g
> The following data were collected by counting the number of operating rooms in use at Tampa General Hospital over a 20-day period: On three of the days only one operating room was used, on five of the days two were used, on eight of the days three were u
> Listed below is a series of experiments and associated random variables. In each case, identify the values that the random variable can assume and state whether the random variable is discrete or continuous.
> The Zagat Restaurant Survey provides food, decor, and service ratings for some of the top restaurants across the United States. For 15 restaurants located in Boston, the average price of a dinner, including one drink and tip, was $48.60. You are leaving
> More and more shoppers prefer to do their holiday shopping online from companies such as Amazon. Suppose we have a group of 10 shoppers; 7 prefer to do their holiday shopping online and 3 prefer to do their holiday shopping in stores. A random sample of
> Suppose N = 15 and r = 4. What is the probability of x = 3 for n = 10?
> According to a 2017 survey conducted by the technology market research firm The Radicati Group, U.S. office workers receive an average of 121 emails per day (Entrepreneur magazine website). Assume the number of emails received per hour follows a Poisson
> According to the National Oceanic and Atmospheric Administration (NOAA), the state of Colorado averages 18 tornadoes every June (NOAA website). (Note: There are 30 days in June.) a. Compute the mean number of tornadoes per day. b. Compute the probability
> To perform a certain type of blood analysis, lab technicians must perform two procedures. The first procedure requires either one or two separate steps, and the second procedure requires either one, two, or three steps. a. List the experimental outcomes
> Emergency 911 calls to a small municipality in Idaho come in at the rate of one every 2 minutes. a. What is the expected number of 911 calls in one hour? b. What is the probability of three 911 calls in five minutes? c. What is the probability of no 911
> The following observations are for two quantitative variables, x and y. Develop a crosstabulation for the data, with x as the row variable and y as the column variable. For x use classes of 10–29, 30–49, and so on; f
> Consider a Poisson distribution with m = 3. a. Write the appropriate Poisson probability function. b. Compute f (2). c. Compute f (1). d. Compute P(x ≥ 2).
> According to a 2017 Wired magazine article, 40% of emails that are received are tracked using software that can tell the email sender when, where, and on what type of device the email was opened (Wired magazine website). Suppose we randomly select 50 rec
> A university found that 20% of its students withdraw without completing the introductory statistics course. Assume that 20 students registered for the course. a. Compute the probability that 2 or fewer will withdraw. b. Compute the probability that exact
> The Census Bureau includes nine states in what it defines as the Northeast region of the United States. Assume that the government is interested in tracking unemployment in these nine states and that the random variable of interest is the number of North
> Three students scheduled interviews for summer employment at the Brookwood Institute. In each case the interview results in either an offer for a position or no offer. Experimental outcomes are defined in terms of the results of the three interviews. a.
> The demand for a product of Carolina Industries varies greatly from month to month. The probability distribution in the following table, based on the past two years of data, shows the company’s monthly demand. a. If the company bases
> Consider the experiment of a worker assembling a product. a. Define a random variable that represents the time in minutes required to assemble the product. b. What values may the random variable assume? c. Is the random variable discrete or continuous?
> Establishing Patient Trust. A psychologist determined that the number of sessions required to obtain the trust of a new patient is either 1, 2, or 3. Let x be a random variable indicating the number of sessions required to gain the patientâ€&#
> Spectrum provides cable television and Internet service to millions of customers. Suppose that the management of Spectrum subjectively assesses a probability distribution for the number of new subscribers next year in the state of New York as follows.
> A technician services mailing machines at companies in the Phoenix area. Depending on the type of malfunction, the service call can take 1, 2, 3, or 4 hours. The different types of malfunctions occur at about the same frequency. a. Develop a probability
> The following data are for 30 observations involving two categorical variables, x and y. The categories for x are A, B, and C; the categories for y are 1 and 2. a. Develop a crosstabulation for the data, with x as the row variable and y as the column v
> Consider the experiment of tossing a coin twice. a. List the experimental outcomes. b. Define a random variable that represents the number of heads occurring on the two tosses. c. Show what value the random variable would assume for each of the experimen
> Simple random sampling uses a sample of size n from a population of size N to obtain data that can be used to make inferences about the characteristics of a population. Suppose that, from a population of 50 bank accounts, we want to take a random sample
> A decision maker subjectively assigned the following probabilities to the four outcomes of an experiment: P(E1) = .10, P(E2) = .15, P(E3) = .40, and P(E4) = .20. Are these probability assignments valid? Explain.
> An experiment with three outcomes has been repeated 50 times, and it was learned that E1 occurred 20 times, E2 occurred 13 times, and E3 occurred 17 times. Assign probabilities to the outcomes. What method did you use?
> Suppose an experiment has five equally likely outcomes: E1, E2, E3, E4, E5. Assign probabilities to each outcome and show that the requirements in equations (4.3) and (4.4) are satisfied. What method did you use?
> A local bank reviewed its credit card policy with the intention of recalling some of its credit cards. In the past approximately 5% of cardholders defaulted, leaving the bank unable to collect the outstanding balance. Hence, management established a prio
> A consulting firm submitted a bid for a large research project. The firm’s management initially felt they had a 50–50 chance of getting the project. However, the agency to which the bid was submitted subsequently requested additional information on the b
> Consider the experiment of tossing a coin three times. a. Develop a tree diagram for the experiment. b. List the experimental outcomes. c. What is the probability for each experimental outcome?
> The prior probabilities for events A1 and A2 are P(A1) = .40 and P(A2) = .60. It is also known that P(A1 ∩ A2) = 0. Suppose P(B ∣ A1) = .20 and P(B ∣ A2) = .05. a. Are A1 and A2 mutually exclusive? Explain. b. Compute P(A1 ∩ B) and P(A2 ∩ B). c. Compute
> Assume that we have two events, A and B, that are mutually exclusive. Assume further that we know P(A) = .30 and P(B) = .40. a. What is P(A ∩ B)? b. What is P(A ∣ B)? c. A student in statistics argues that the concepts of mutually exclusive events and in
> The Flying Pig is a marathon (26.2 mile long) running race held every year in Cincinnati, Ohio. Suppose that the following data show the ages for a sample of 40 marathon runners. a. Construct a stretched stem-and-leaf display. b. Which age group had th
> Suppose that we have two events, A and B, with P(A) = .50, P(B) = .60, and P(A ∩ B) = .40. a. Find P(A ∣ B). b. Find P(B ∣ A). c. Are A and B independent? Why or why not?
> How many permutations of three items can be selected from a group of six? Use the letters A, B, C, D, E, and F to identify the items, and list each of the permutations of items B, D, and F.
> Survey on Car Rentals. A survey of magazine subscribers showed that 45.8% rented a car during the past 12 months for business reasons, 54% rented a car during the past 12 months for personal reasons, and 30% rented a car during the past 12 months for bot
