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Chapter: 10 -Problem: 55 >> The authors of the paper “Changes in Quantity, Spending, and Nutritional Characteristics of Adult, Adolescent and Child Urban Corner Store Purchases After an Environmental Intervention” (Preventative Medicine [2015]: 81–85) wondered if increasing the availability of healthy food options would also increase the amount people spend at the corner store. They collected data from a representative sampl
Answer Preview: a The fact that the sample standard deviation is greater than t…

, Chapter: 14 -Problem: 14 >> If we knew the width and height of cylindrical tin cans of food, could we predict the volume of these cans with precision and accuracy?a. Give the equation that would allow us to make such predictions.b. Is the relationship between volume and its predictors, height and width, a linear one?c. Should we use an additive multiple regression model to predict a volume of a can from its height and width?
Answer Preview: a. The equation to calculate the volume of a cylindrical tin can is given by: Volume = * (radius)^2 …

, Chapter: 4 -Problem: 29 >> Morningstar is an investment research firm that publishes some online educational materials. The materials for an online course called “Looking at Historical Risk” (news.morningstar.com/classroom2 /course.asp?docId=2927&page=2&CN=com, retrieved August 3, 2016) included the following paragraph referring to annual return (in percent) for investment funds: Using standard deviation as a measure of ris
Answer Preview: a The standard deviation of percent return is a reasonable measur…

, Chapter: 10 -Problem: 34 >> The article “Euthanasia Still Acceptable to Solid Majority in U.S.” (gallup.com, June 24, 2016, retrieved November 29, 2016) summarized data from a survey of 1025 adult Americans. When asked if doctors should be able to end a terminally ill patient’s life by painless means if requested to do so by the patient, 707 of those surveyed responded yes. For purposes of this exercise, assume that it is re
Answer Preview: a where p is the actual proportion of adult Americans who believe that doctors …

, Chapter: 4 -Problem: 15 >> A sample of n = 5 college students yielded the following observations on number of traffic citations for a moving violation during the previous year:Calculate s2 and s. Transcribed Image Text: xs = 2 = = 3 X4 0 = Ex 0 = ²x I = '¹x
Answer Preview: To calculate the sample variance (s^2) and sample standard deviation (s) for the given observations, …

, Chapter: 5 -Problem: 61 >> Refer to the heart transplant data given in the previous exercise.a. Find a transformation of x and/or y that straightens the plot. Construct a scatterplot for your transformed variables.b. Using the transformed variables from Part (a), fit a least-squares line and use it to predict the number waiting for a heart transplant in 2016 (Year 11).c. The prediction made in Part (b) involves prediction f
Answer Preview: a One transformation to straighten the plot is x year 2 and y number of heart tra…

, Chapter: 11 -Problem: 70 >> Use the information given in the previous exercise to calculate a 95% bootstrap confidence interval to estimate the mean difference in movement, OFF ? CL. Interpret the interval in context. You can make use of the Shiny apps in the collection at statistics.cengage.com/PSO6e/Apps.html. Previous exercise
Answer Preview: Different simulations will produce different …

, Chapter: 6 -Problem: 29 >> Of the 60 movies reviewed last year by two critics on their joint television show, Critic 1 gave a “thumbs-up” rating to 15, Critic 2 gave this rating to 20, and 10 of the movies were rated thumbs-up by both critics. Suppose that 1 of these 60 movies is randomly selected. a. Given that the movie was rated thumbs-up by Critic 1, what is the probability that it also received this rating from Critic
Answer Preview: To solve this problem, we can use conditional probability. Let's define the events: A: The movie was …

, Chapter: 3 -Problem: 24 >> The data in the accompanying table are from the Organization for Economic Co-operation and Development (data.oecd.org/eduatt/population -with-tertiary-education.htm, retrieved February 18, 2018). Entries in the table are the percentage of 25- to 34-year-old people who have completed a 4-year college degree for 27 countries in 2016.? a. Construct a histogram of these data using the class intervals
Answer Preview: a b A typical percentage of people age25 to 34 with a …

, Chapter: 11 -Problem: 64 >> Use the information given in the previous exercise to construct a 95% bootstrap confidence interval to estimate the difference in mean average working heart rates for the driver in teams of two firefighters and the driver in teams of from three to five firefighters. Interpret the interval in context. You can make use of the Shiny apps in the collection at statistics.cengage.com/PSO6e/Apps.html.?
Answer Preview: Different simulations will produce different results One simulation resulte…

, Chapter: 7 -Problem: 59 >> A city ordinance requires that a smoke detector be installed in all residential housing. There is concern that too many residences are still without detectors, so a costly inspection program is being contemplated. Let ? be the proportion of all residences that have a detector. A random sample of 25 residences is selected. If the sample strongly suggests that ? < .80 (less than 80% have detectors),
Answer Preview: To answer these questions, we need to perform a hypothesis test for the proportion based on the decision rule given and calculate the corresponding pr…

, Chapter: 4 -Problem: 52 >> The paper ?Study of the Flying Ability of Rhynchophorus ferrugineus Adults Using a Computer-Monitored Mill? (Bulletin of Entomological Research [2014]: 462?467) summarized data from a study of red palm weevils, a pest that is a threat to palm trees. The following frequency distribution from the paper was constructed using the longest flight (in meters) observed for 132 weevils.? Estimate the appr
Answer Preview: a Because 132 x 0 54 71 28 we are looking for the data valu…

, Chapter: 11 -Problem: 28 >> The paper referenced in the previous exercise also compared the reported heights and weights to actual measured heights and weights for a sample of 1052 female college students selected from eight different universities. The resulting data are summarized in the accompanying table. You can assume that this sample is representative of female college students.? a. Carry out a hypothesis test to dete
Answer Preview: a 1 d the difference in the paired means reported weight actual weight 2 H 0 d 0 3 H a d 0 4 0 05 5 …

, Chapter: 6 -Problem: 71 >> A company that manufactures video cameras produces a basic model and a deluxe model. Over the past year, 40% of the cameras sold have been the basic model. Of those buying the basic model, 30% purchase an extended warranty, whereas 50% of all purchasers of the deluxe model buy an extended warranty. If you learn that a randomly selected purchaser bought an extended warranty, what is the probability
Answer Preview: To find the probability that a randomly selected purchaser has a basic model given that they bought …

, Chapter: 3 -Problem: 26 >> The accompanying relative frequency table is based on data from the 2016 College Bound Seniors Report (collegeboard.org, retrieved February 18, 2018).? a. Construct a relative frequency histogram for SAT critical reading score for males.? b. Construct a relative frequency histogram for SAT critical reading score for females.? c. Based on the histograms from Parts (a) and (b), write a few sentences
Answer Preview: a b The distribution of maximum wind speed…

, Chapter: 9 -Problem: 68 >> Teams in the National Football League (NFL) are given a ?bye? during one week of the season, when they can rest and not play a game. This may provide an advantage for the team in the next game they play after a bye. In 2016, each of the 32 NFL teams was granted a bye during one of the weeks of the season. The following table contains the team name and the number of points they won by or lost by in
Answer Preview: a A boxplot shown below was constructed Note that the boxplot indicates an outlier i…

, Chapter: 5 -Problem: 30 >> The paper “Postmortem Changes in Strength of Gastropod Shells” (Paleobiology [1992]: 367–377) included scatterplots of data on x = shell height (in centimeters) and y = breaking strength (in newtons) for a sample of n = 38 hermit crab shells. The least-squares line wasa. What are the slope and the intercept of this line?b. When shell height increases by 1 cm, by how much does breaking strength ten
Answer Preview: a. The slope of the least-squares line is 244 9, and the intercept is -275 1. …

, Chapter: 5 -Problem: 11 >> The paper “The Relationship Between Cell Phone Use, Academic Performance, Anxiety, and Satisfaction with Life in College Students” (Computers in Human Behavior [2014]: 343–350) described a study of cell phone use among undergraduate college students at a public university. The paper reported that the value of the correlation coefficient between x = Cell phone use (measured as total amount of time
Answer Preview: a The value of the correlation coefficient is negative which suggests that students who …

, Chapter: 11 -Problem: 67 >> A new set of cognitive training modules called ONTRAC was developed to help children with attention deficit hyperactivity disorder (ADHD) to improve focus and to more easily dismiss distractions (“Training Sensory Signal-to-Noise Resolution in Children with ADHD in a Global Mental Health Setting,” Translational Psychiatry, April 12, 2016, nature.com/tp/journal/v6/n4/full/tp201645a.html, retrieved
Answer Preview: a Because the sample sizes for each treatment group are smaller than 30 we must b…

, Chapter: 6 -Problem: 18 >> Consider the chance experiment in which both tennis racket head size and grip size are noted for a randomly selected customer at a particular store. The six possible outcomes (simple events) and their probabilities are displayed in the following table:a. The probability that grip size is 4(1/2) in. (event A) is P(A) = P(O2 or O5) = .20 + .15 = .35. How would you interpret this probability?b. Use t
Answer Preview: a. The probability that grip size is 4(1/2) in. (event A) is calculated by adding the individual pro…

, Chapter: 3 -Problem: 14 >> The report ?Findings From the 2014 College Senior Survey? (Higher Education Research Institute, December 2014) summarizes data collected from more than 13,000 college seniors across the United States. One question in the survey asked students to rate themselves based on their critical thinking skills. For engineering majors, 60.4% rated critical thinking as ?a major strength? while 39.6% did not s
Answer Preview: The largest deviations in relative frequency between Major Strength and Not …

, Chapter: 10 -Problem: 6 >> CareerBuilder.com conducted a survey to learn about the proportion of employers who perform background checks when evaluating a job candidate (“Majority of Employers Background Check Employees . . . Here’s Why,” November 17, 2016, retrieved November 19, 2016). Suppose you are interested in determining if the resulting data provide convincing evidence in support of the claim that more than two-thir
Answer Preview: where p is the prop…

, Chapter: 7 -Problem: 117 >> Bob and Lygia are going to play a series of Trivial Pursuit games. The first person to win four games will be declared the winner. Suppose that outcomes of successive games are independent and that the probability of Lygia winning any particular game is .6. Define a random variable x as the number of games played in the series.a. What is p(4)?b. What is p(5)?c. Determine the probability distributi
Answer Preview: To solve this problem, we'll use the binomial probability formula, as each game's outcome is a binary event (win or lose), and the outcomes are indepe…

, Chapter: 6 -Problem: 30 >> According to The Chronicle for Higher Education Almanac (2016), there were 1,003,329 Associate degrees awarded by U.S. community colleges in the 2013–2014 academic year. A total of 613,034 of these degrees were awarded to women.a. If a person who received a degree in 2013–2014 was selected at random, what is the probability that the selected student is female?b. What is the probability that the se
Answer Preview: a b P the se…

, Chapter: 11 -Problem: 23 >> Many runners believe that listening to music while running enhances their performance. The authors of the paper ?Effects of Synchronous Music on Treadmill Running Among Elite Triathletes? (Journal of Science and Medicine in Sport [2012]: 52?57) wondered if this was true for experienced runners. They recorded time to exhaustion for 11 triathletes while running on a treadmill at a speed determined t
Answer Preview: 1 d mean difference in the paired means motivational music no music 2 H 0 d 0 3 H a d 0 4 0 05 5 6 W…

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, Chapter: 3 -Problem: 58 >> The following data on percentage increase in population between 2010 and 2017 for the 50 U.S. states and the District of Columbia (DC) were calculated using information from the U.S. Census Bureau (factfinder.census.gov /faces/tableservices/jsf/pages/productview .xhtml?pid=PEP_2017_PEPANNRES&src=pt, retrieved April 10, 2018). Each state is also classified as belonging to either the eastern or west
Answer Preview: a b The distribution is positively skewed The center of the dis…

, Chapter: 10 -Problem: 7 >> A national survey of 1012 adult Americans conducted by Gallup (“Americans Still Generally Upbeat About Personal Finances,” gallup.com, January 25, 2016, retrieved November 16, 2016) asked survey participants if they thought they were in better financial shape than they were 1 year ago. Suppose that you want to determine if the survey data provide convincing evidence that a majority of adult Americ
Answer Preview: H 0 p 0 5 versus H a p …

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, Chapter: 5 -Problem: 28 >> The data given in the previous exercise on x = Callto-shock time (in minutes) and y = Survival rate (percent) were used to compute the equation of the least-squares line, which was y? = 101.33 - 9.30xThe newspaper article “FDA OKs Use of Home Defibrillators” (San Luis Obispo Tribune, November 13, 2002) reported that “every minute spent waiting for paramedics to arrive with a defibrillator lowers t
Answer Preview: Since the slope of the least squares l…

, Chapter: 10 -Problem: 85 >> Major League Baseball (MLB) includes two groups of teams, in two ?leagues.? There are 15 teams in each of the American League (AL) and the National League (NL). Since 1997, teams in each of the leagues play teams from the other league in ?interleague? regular-season games. One way to determine whether one league is stronger than the other is to consider the interleague winning percentages for all
Answer Preview: a The fact that the sample size n 15 is smaller than 30 indicates that the methods based on the t di…

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, Chapter: 4 -Problem: 26 >> The paper referenced in the previous exercise also gave summary statistics and graphs for the reaction time of drivers who were not listening to audiobooks. Data on reaction time (in milliseconds) consistent with those summary statistics for 10 drivers not listening to audiobooks are given here. 961 904 1010 976 1018 1041 1004 981 995 991 a. Use the data given in this exercise and the data given i
Answer Preview: a b The range of reaction times for those listening to audiobooks 1108 806 248 millise…

, Chapter: 8 -Problem: 8 >> Simulate sampling from the population of Exercise 8.7 by using four slips of paper individually marked 1, 2, 3, and 4. Select a sample of size 2 without replacement, and calculate x. Repeat this process 50 times, and construct a density histogram of the 50 x?. values. How does this sampling distribution compare to the actual sampling distribution of x. from Exercise 8.7, Part (b)? Exercise 8.7
Answer Preview: To simulate sampling from the population we can randomly select two slips of paper without replaceme…

, Chapter: 11 -Problem: 52 >> The Bureau of Labor Statistics report referenced in the previous exercise also indicated that 7.3% of high school graduates were unemployed in October 2013 and 5.7% of high school graduates were unemployed in October 2014. Suppose that the reported percentages were based on independently selected representative samples of 400 high school graduates in each of these two years.a. Construct and interp
Answer Preview: a Check of Conditions We are told that the samples are representative of the populations high sc…

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, Chapter: 3 -Problem: 40 >> The accompanying table gives data from a survey of new car owners conducted by J.D. Power and Associates (USA TODAY, usatoday.com, March 29, 2016). For each brand of car sold in the United States, data on a quality rating (defects per 100 cars, so lower numbers indicate higher quality) and a customer satisfaction rating (called the APEAL rating) are given in the accompanying table. The APEAL ratin
Answer Preview: a b No Customer satisfaction does not seem to be related to car …

, Chapter: 9 -Problem: 41 >> The paper “The Effects of Adolescent Volunteer Activities on the Perception of Local Society and Community Spirit Mediated by Self-Conception” (Advanced Science and Technology Letters [2016]: 19–23) describes a survey of a large representative sample of middle school children in South Korea.One question in the survey asked how much time per year the children spent in volunteer activities. The samp
Answer Preview: a If the distribution of volunteer times is approximately normal for the sample standard deviation o…

, Chapter: 10 -Problem: 54 >> The report “Majoring in Money: How American College Students Manage Their Finances” (Sallie Mae, 2016, news/salliemae.com, retrieved December 24, 2016) includes data from a survey of college students. Each person in a representative sample of 793 college students was asked if they had one or more credit cards and if so, whether they paid their balance in full each month. There were 500 who paid in
Answer Preview: 1 mean credit card balance of college students who pay their credit card balance in full e…

, Chapter: 6 -Problem: 89 >> A student has a box containing 25 computer disks, of which 15 are blank and 10 are not. She randomly selects disks one by one and examines each one, terminating the process only when she finds a blank disk. What is the probability that she must examine at least two disks?
Answer Preview: Probability of not selecting a blank disk on the first attempt: The student has 25 disks, of which 1…

, Chapter: 2 -Problem: 3 >> The article “Why We Fall for This” (AARP Magazine, May/June 2011) described a study in which a business professor divided his class into two groups. He showed students a mug and then asked students in one of the groups how much they would pay for the mug. Students in the other group were asked how much they would sell the mug for if it belonged to them. Surprisingly, the average value assigned to
Answer Preview: This was an experiment since …

, Chapter: 6 -Problem: 107 >> A study of the impact of seeking a second opinion about a medical condition is described in the paper “Evaluation of Outcomes from a National Patient-Initiated Second Opinion Program” (The American Journal of Medicine [2015], 1138e25– 1138e33). Based on a review of 6791 patientinitiated second opinions, the paper states the following: “Second opinions often resulted in changes in diagnosis (14.8%)
Answer Preview: a P D 0 148 P T 0 374 and P D T 0 106 b P D …

, Chapter: 10 -Problem: 36 >> The article “How to Block Nuisance Calls” (The Guardian, November 7, 2015) reported that in a survey of mobile phone users, 70% of those surveyed said they had received at least one nuisance call to their mobile phone in the last month. Suppose that this estimate was based on a representative sample of 600 mobile phone users. These data can be used to determine if there is evidence that more than
Answer Preview: a Because the null hypothesis was rejected there is convincing evidence that the p…

, Chapter: 7 -Problem: 1 >> The recipe calls for four fresh eggs for each quiche. A Salt Lake County Health Department inspector paid a visit recently and pointed out that research by the Food and Drug Administration indicates that one in four eggs carries salmonella bacterium, so restaurants should never use more than three eggs when preparing quiche. The manager on duty wondered aloud if simply throwing out three eggs from
Answer Preview: 1. The folly of the statement: The manager's proposal of throwing out three eggs from each dozen and using the remaining nine in four-egg quiches is not a valid solution to mitigate the risk of salmon…

, Chapter: 6 -Problem: 7 >> A new model of laptop computer can be ordered with one of three screen sizes (10 inches, 12 inches, 15 inches) and one of four hard drive sizes (50 GB, 100 GB, 150 GB, and 200 GB). Consider the chance experiment in which a laptop order is selected and the screen size and hard drive size are recorded.a. Display possible outcomes using a tree diagram.b. Let A be the event that the order is for a lap
Answer Preview: a b i AC 15 50 15 100 15 150 15 200 i…

, Chapter: 8 -Problem: 29 >> The article “Fewer Americans Are Reading, But Don’t Blame the Millennials” (Los Angeles Times, October 9, 2016) indicates that 80% of millennials (those age 18 to 29) have read a book in the last year. Suppose that this is the actual percentage for the population of all millennials. Consider a sample proportion p? that is based on a random sample of 225 millennials.a. If p = 0.80, what are the mea
Answer Preview: a If p 0 8 then 0 8 p and b If p 0 7 then p c When p 0 8 np 225 0 8 180 an…

, Chapter: 10 -Problem: 79 >> At one point during the 2015 NFL season, head coach Bill Belichick and the New England Patriots had won 19 of their past 25 called coin flips at the beginning of NFL games (?For Bill Belichick, Patriots? Strategy Is No Flip of theCoin,? bostonglobe.com/sports/2015/11/04? /pnotes/vFNt235bsK8x3JLZ6FJdtK/story.html, November 4, 2015, retrieved May 6, 2017). Suppose that these 25 coin toss calls can b
Answer Preview: a We should test the hypotheses H 0 p 0 50 versus H a p 0 50 where p is the proportionof coin flip c…

, Chapter: 4 -Problem: 1 >> The Highway Loss Data Institute publishes data on repair costs resulting from a 5-mph crash test of a car moving forward into a flat barrier. The following table gives data for 10 midsize luxury cars tested in October 2002:Compute the values of the mean and the median. Why are these values so different? Which of the mean and median is more representative of the data set, and why?
Answer Preview: To compute the mean and median for the given data set, we need to first list the repair costs in asc…

, Chapter: 3 -Problem: 18 >> The previous exercise gave data on seat belt use for each of the 50 U.S. states and the District of Columbia (“Traffic Safety Facts,” National Highway Traffic Safety Administration, June 2015). The observations represent the percentage of drivers wearing seat belts in a large nationwide observational survey. Some, but not all, states enforce seat belts laws. Below are the seat belt usage data divi
Answer Preview: a b Although there is state to state variability in both the stat…

, Chapter: 8 -Problem: 4 >> Consider a population consisting of the following five values, which represent the number of video downloads during the academic year for each of five housemates: 8    14    16    10     11Compute the mean of this population.
Answer Preview: 8 14…

, Chapter: 11 -Problem: 71 >> The article ?Rapid Evolutionary Response to a Transmissible Cancer in Tasmanian Devils? (nature .com/articles/ncomms12684, retrieved December 20, 2016) describes the spread of devil facial tumor disease (DFTD), which is a fatal form of cancer that swept through the Tasmanian devil population near the beginning of the 21st century. Researchers studied the genetic reaction of the Tasmanian devils by
Answer Preview: a In order to use the large sample hypothesis test for the difference in two population proportions …

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, Chapter: 5 -Problem: 5 >> Each year the Harris Poll surveys Americans on a number of issues. It uses responses to several questions to calculate a “Happiness” index that measures overall happiness. The article “Latest Happiness Index RevealsAmerican Happiness at All-Time Low,” theharrispoll.com  /health-and-life/American-Happiness_at-All-Time-Low .html, retrieved April 21, 2017) included the happiness index for the 7 years
Answer Preview: a r 0 394 b r 0 664 c There is a stronger relationship between …

, Chapter: 7 -Problem: 108 >> The figure on the next page appeared in the paper ?EDTA-Extractable Copper, Zinc, and Manganese in Soils of the Canterbury Plains? (New Zealand Journal of Agricultural Research [1984]: 207?217). A large number of topsoil samples were analyzed for manganese (Mn), zinc (Zn), and copper (Cu), and the resulting data were summarized using histograms. The investigators transformed each data set using lo
Answer Preview: Yes In each case the trans…

, Chapter: 11 -Problem: 51 >> The Bureau of Labor Statistics (bls.gov/opub /ted/2014/ted_20141112.htm, retrieved December 13, 2016) reported that 3.8% of college graduates were unemployed in October 2013 and 3.1% of college graduates were unemployed in October 2014. Suppose that the reported percentages were based on independently selected representative samples of 500 college graduates in each of these two years. Construct an
Answer Preview: Check of Conditions We are told that the two samples are independently selected …

, Chapter: 13 -Problem: 71 >> The employee relations manager of a large company was concerned that raises given to employees during a recent period might not have been based strictly on objective performance criteria. A sample of n = 20 employees was selected, and the values of x, a quantitative measure of productivity, and y, the percentage salary increase, were determined for each one. A computer package was used to fit the
Answer Preview: To determine whether the percentage raise (y) is linearly related to productivity (x), the employee …

, Chapter: 3 -Problem: 16 >> The paper ?State-Level Cancer Mortality Attributable to Cigarette Smoking in the United States? (JAMA Internal Medicine [2016]: 1792?1798) included the following state estimates of the total number cancer deaths attributable to cigarette smoking in 2014.? a. Construct a stem-and-leaf display using thousands as the stems and truncating the leaves to the tens digit.? b. Write a few sentences descr
Answer Preview: a b The distribution has just one peak at the lowest class …

, Chapter: 9 -Problem: 40 >> USA TODAY reported that the average amount of money spent on coffee drinks each month is $78.00 (USA TODAY Snapshot, November 4, 2016).a. Suppose that this estimate was based on a representative sample of 20 adult Americans. Would you recommend using the one-sample t confidence interval to estimate the population mean amount spent on coffee for the population of all adult Americans? Explain why or
Answer Preview: a The two necessary conditions are 1 that the sample of adult Americans is a rando…

, Chapter: 11 -Problem: 50 >> The report “Raising Kids and Running a Household: How Working Parents Share the Load” (November 4, 2015, Pew Research Center, pewresearch.org, retrieved December 12, 2016) described a survey of parents of children under the age of 18. Each person in a representative sample of 825 working fathers and a sample of 586 working mothers was asked if balancing the responsibilities of a job and a family w
Answer Preview: No It is not appropriate to use the two sample z test because th…

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, Chapter: 6 -Problem: 3 >> Consider the chance experiment in which the type of transmission automatic (A) or manual (M)—is recorded for each of the next two cars purchased from a certain dealer.a. What is the set of all possible outcomes (the sample space)?b. Display the possible outcomes in a tree diagram.
Answer Preview: a AA …

, Chapter: 7 -Problem: 66 >> Suppose that 90% of all registered California voters favor banning the release of information from exit polls in presidential elections until after the polls in California close. A random sample of 25 registered California voters is to be selected.a. What is the probability that more than 20 favor the ban?b. What is the probability that at least 20 favor the ban?c. What are the mean value and stan
Answer Preview: Let x number of voters who favor the ban Then x is binomially di…

, Chapter: 9 -Problem: 63 >> In mid-2016 the United Kingdom (UK) withdrew from the European Union (an event known as ?Brexit?), causing economic concerns throughout the world. One indicator that economists use to monitor the health of the economy is the proportion of residential properties offered for sale at auction that are successfully sold. An article titled ?Going, Going, Gone through the Roof?Sky?s the Limit at Auction?
Answer Preview: a Yes it would be appropriate to use the large sample confidence interval for a population proportio…

, Chapter: 13 -Problem: 33 >> The accompanying data on x = U.S. population (millions) and y = crime index (millions) appeared in the article “The Normal Distribution of Crime” (Journal of Police Science and Administration [1975]: 312–318). The author comments that “The simple linear regression analysis remains one of the most useful tools for crime prediction.” When observations are made sequentially in time, the residuals or
Answer Preview: To determine whether the simple linear regression model is appropriate, we need to calculate the residuals and plot the (x, residual) pairs. Residuals …

, Chapter: 5 -Problem: 57 >> Food intake of grazing animals is limited by the rate grass can be chewed and swallowed, as well as the rate at which food can be digested. The authors of the paper “What Constrains Daily Intake in Thomson’s Gazelles?” (Ecology [1999]: 2338–2347) observed the grazing activity of captive Thomson’s gazelles. They recorded grazing rate (amount of grass eaten, in grams per minute) and biomass of the g
Answer Preview: I would recommend function d as the best description of th…

, Chapter: 7 -Problem: 32 >> The density curve for the random variable w (the sum of two wait times) is given in the previous exercise. What is the probability that w is between 10 and 30? It might be easier first to find the probability that w is not between 10 and 30.
Answer Preview: P 10 w 3…

, Chapter: 11 -Problem: 29 >> The paper “Driving Performance While Using a Mobile Phone: A Simulation Study of Greek Professional Drivers” (Transportation Research Part F [2016]: 164–170) describes a study in which 50 Greek male taxi drivers drove in a driving simulator. In the simulator, they were asked to drive following a lead car. On one drive, they had no distractions and the average distance between the driver’s car and
Answer Preview: 1 mean difference in the paired means no distraction talking on mobile …

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, Chapter: 6 -Problem: 22 >> Consider the chance experiment described in the previous exercise. a. For customers who purchase a single book, the estimated probabilities for the different possible outcomes are given in the cells of the accompanying table. What is the probability that a randomly selected single-book purchase will be for a book in print format (hardcover or paperback)? b. Show two different ways to calculate t
Answer Preview: a 0 15 0 08 0 45 …

, Chapter: 7 -Problem: 4 >> A point is randomly selected from the interior of the square pictured. Let x denote the distance from the lower left-hand corner A of the square to the selected point.? a. What are possible values of x? b. Is x a discrete or a continuous variable? See Example 7.3. Transcribed Image Text: B. 1 foot
Answer Preview: a The random v…

, Chapter: 10 -Problem: 77 >> Data from a large study carried out in 2008 were used to estimate that 10% of all smokers who quit smoking are smoking again after 1 year (“Relapse to Smoking After 1 Year of Abstinence: A Meta-analysis,” ncbi.nlm.nih.gov/pmc/articles /PMC2577779/, June 8, 2008, retrieved May 6, 2017). The outcomes of many surgical procedures are improved for patients who are not smoking.In a University of Kansas
Answer Preview: a These data should not be analyzed using a large sample hypothesis test for one population propo…

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, Chapter: 3 -Problem: 49 >> The figure at the top left of the next page is from the Fall 2008 Census Enrollment Report at Cal Poly, San Luis Obispo. It uses both a pie chart and a segmented bar chart to summarize data on ethnicity for students enrolled at the university in Fall 2008. a. Use the information in the graphical display to construct a single segmented bar chart for the ethnicity data. b. Do you think that the orig
Answer Preview: a b The graphical display created in Part a is more informative since it gives an accurate re…

, Chapter: 6 -Problem: 118 >> Suppose that a box contains 25 light bulbs, of which 20 are good and the other 5 are defective. Consider randomly selecting three bulbs without replacement.Let E denote the event that the first bulb selected is good, F be the event that the second bulb is good, and G represent the event that the third bulb selected is good.a. What is P(E)?b. What is P(F|E)?c. What is P(G|E ? F)?d. What is the prob
Answer Preview: a P E 20 25 4 5 …

, Chapter: 10 -Problem: 52 >> The report “2016 Salary Survey Executive Summary” (National Association of Colleges and Employers, naceweb.org/uploadedfiles/files/2016 /publications /executive summary/2016-nace-salary-survey-fall -executive-summary.pdf, retrieved December 24, 2016) states that the mean yearly salary offer for students graduating with mathematics and statistics degrees in 2016 is $62,985. Suppose that a random sa
Answer Preview: 1 mean salary offering for mathematics and statistics graduates at this university 2 H 0 62985 3 …

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, Chapter: 6 -Problem: 18 >> Consider the chance experiment described in the previous exercise. Suppose that the probability of an overnight delivery selection is 0.1, the probability of a second-day delivery selection is 0.3, and the probability of a standard-delivery selection is 0.4. Find the following probabilities.a. the probability that a randomly selected online purchase selects delivery to the nearest store for custom
Answer Preview: a 1 0 …

, Chapter: 7 -Problem: 14 >> Refer to the previous exercise. Suppose that because of the high rate of false-positives for the drug test, Mumble.com has instituted a mandatory independent second test for those who test positive on the first test.a. If one employee is selected at random, what is the probability that the selected employee uses drugs and tests positive twice?b. If one employee is selected at random, what is the p
Answer Preview: a 0 1 0 9 0 9 0 081 b 0 1 0 9 0 9 0 9 0 05 0 05 0 08325 c d P n…

, Chapter: 11 -Problem: 27 >> The authors of the paper “Concordance of Self- Report and Measured Height and Weight of College Students” (Journal of Nutrition, Education and Behavior [2015]: 94–98) used a paired-samples t test to reach the conclusion that male college students tend to over-report both weight and height. This conclusion was based on a sample of 634 male college students selected from eight different universities
Answer Preview: a 1 d the difference in the paired means reported weight actual weight 2 H 0 d 0 3 H a d 0 4 0 05 5 …

, Chapter: 5 -Problem: 47 >> The paper “Crop Improvement for Tropical and Subtropical Australia: Designing Plants for Difficult Climates” (Field Crops Research [1991]: 113–139) gave the following data on x = crop duration (in days) for soybeans and y = crop yield (in tons per hectare):a. Construct a scatterplot of the data. Do you think the least-squares line will give accurate predictions? Explain.b. Delete the observation w
Answer Preview: To answer the questions, let's first interpret the given data: x: Crop duration (in days) for soybea…

, Chapter: 5 -Problem: 6 >> The amount of money spent each year on science, space, and technology in the United States (in millions of dollars) and the amount of money spent on pets in the United States (in billions of dollars) for the years 2000 to 2009 were used to construct the graph below. (The data are from the web site tylervigen.com/spurious correlations, accessed August 28, 2016). Based on these time series plots, wo
Answer Preview: The correlation coefficient will be positive …

, Chapter: 8 -Problem: 22 >> The thickness (in millimeters) of the coating applied to hard drives is one characteristic that determines the usefulness of the product. When no unusual circumstances are present, the thickness (x) has a normal distribution with a mean of 2 mm and a standard deviation of 0.05 mm. Suppose that the process will be monitored by selecting a random sample of 16 drives from each shift’s production and
Answer Preview: a The distribution of x is normal with mean 2 and stand…

, Chapter: 11 -Problem: 53 >> The report “The New Food Fights: U.S. Public Divides Over Food Science” (December 1, 2016, pewinternet.org, retrieved December 10, 2016) states that younger adults are more likely to see  foods with genetically modified ingredients as being bad for their health than older adults. This statement is based on a representative sample of 178 adult Americans age 18 to 29 and a representative sample of 4
Answer Preview: a Yes Let p 1 0 48 and p 2 0 38 n 1 178 and n 2 427 where the 1 subscript indicatesthe age 18 29 gro…

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, Chapter: 5 -Problem: 45 >> The first Batman movie was made over 50 years ago in 1966. Over the years, Batman has been played on screen by a number of actors and even by a Lego figure in the Lego Batman movies. In the original comic books, Batman was 188 centimeters tall (about 6'2") and weighed 95 kilograms (about 210 pounds). The article ?50 Years of Batman on Film: How Has His Physique Changed?? (economist.com, March 28,
Answer Preview: a b The residual plot has one observation the Lego Batman a…

, Chapter: 9 -Problem: 35 >> In 2010, the online security firm Symantec estimated that 63% of computer users don’t change their passwords very often (cnet.com/news/survey-63-dont -change passwords-very-often, retrieved November 19, 2016). Suppose that you want to carry out a new survey to estimate the proportion of students at your school who do not change their password.a. What is the required sample size if you want to esti
Answer Preview: a Assuming a 95 confidence level and using the preliminary estimate of p 0 63 Th…

, Chapter: 9 -Problem: 67 >> The authors of the paper ?Sex Differences in Time Perception During Smoking Abstinence? (Nicotine and Tobacco Research [2015]: 449?454) investigated how nicotine withdrawal affects time perception and decision making. In this study, 21 male smokers were asked to abstain from smoking for 24 hours. After 24 hours, they were shown a demo screen with a green cross that changed to a red cross after a p
Answer Preview: a The sample size of n 21 is smaller than 30 so the …

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, Chapter: 4 -Problem: 24 >> In addition to the prices of the highly-rated smartphones given in the previous exercise, Consumer Reports also gave the prices of the seven smartphones that received the lowest ratings. Those prices (in dollars) were 110 130 100 145 200 180 135 Comment on how the highest-rated smartphones and the lowest rated smartphones differ with respect to price and price variability.
Answer Preview: For the lowest rated smartphones mean 142 90 variance 1298 8 and standard deviation 36 …

, Chapter: 7 -Problem: 57 >> Information Security Buzz provides news for the information security community. In an article published on September 24, 2016, it reported that based on a large international survey of Internet users, 60% of Internet users have installed security solutions on all of the devices they use to access the Internet (informationsecuritybuzz.com /articles/21-29-60-kaspersky-lab-presents-first -cybersecuri
Answer Preview: a b Therefore more than 15 have secur…

, Chapter: 10 -Problem: 29 >> In a survey conducted by CareerBuilder.com, employers were asked if they had ever fired an employee for shopping online while at work (“Cyber Monday Shopping at Work? You’re Not Alone,” November 22, 2016, retrieved November 30, 2016). Of the 2379 employers responding to the survey, 262 said they had fired an employee for shopping online while at work. Suppose that it is reasonable to assume that t
Answer Preview: 1 p proportion of all employers in the U S who have fired an employee for holid…

, Chapter: 5 -Problem: 15 >> Each individual in a sample was asked to indicate on a quantitative scale how willing he or she was to spend money on the environment and also how strongly he or she believed in God (“Religion and Attitudes Toward the Environment,” Journal for the Scientific Study of Religion [1993]: 19–28). The resulting value of the sample correlation coefficient was r = ?.085. Would you agree with the stated co
Answer Preview: To determine whether stronger support for environmental spending is associated with a weaker degree …

, Chapter: 4 -Problem: 7 >> The report ?State of the News Media 2015? (Pew Research Center, April 29, 2015) published the accompanying circulation numbers for 15 news magazines (such as Time and The New Yorker) for 2014:? Explain why the average may not be the best measure of a typical value for this data set.
Answer Preview: The dotplot of circulation numbers reproduced below shows that the di…

, Chapter: 7 -Problem: 50 >> Consider the random variables xR and xB defined in the previous exercise.a. Suppose that you are offered a choice of the following two games:Game 1: Pay $7 to play, and you win y1 dollars, where y1 = xR + xB.Game 2: Doesn’t cost anything to play initially, but you “win” 3y2 dollars, where y2 = xR + xB. If y2 is negative, you must pay that amount; if it is positive, you receive that amount.For Game
Answer Preview: a b c For both of the games the mean of the money gained is 0 The …

, Chapter: 10 -Problem: 11 >> The article “Facebook Use and Academic Performance Among College Students,” Computers in Human Behavior [2015]: 265–272) estimated that 70 percent of students at a large public university in California who are Facebook users log into their Facebook profiles at least six times a day. Suppose that you plan to select a random sample of 400 students at your college. You will ask each student in the sa
Answer Preview: H 0 p 0 7 versus H a p 0 7 wher…

, Chapter: 13 -Problem: 72 >> The article “Statistical Comparison of Heavy Metal Concentrations in Various Louisiana Sediments” (Environmental Monitoring and Assessment [1984]: 163–170) gave the accompanying data on depth (m), zinc concentration (ppm), and iron concentration (%) for 17 core samples.a. Using a .05 significance level, test appropriate hypotheses to determine whether a correlation exists between depth and zinc co
Answer Preview: a. Hypothesis Testing for Correlation between Depth and Zinc Concentration: Null Hypothesis (H0): There is no correlation between depth and zinc concentration ( = 0). Alternative Hypothesis (Ha): Ther…

, Chapter: 6 -Problem: 48 >> The paper ?Accuracy and Reliability of Self-Reported Weight and Height in the Sister Study? (Public Health Nutrition [2012]: 989?999) investigates whether women accurately report their weight. The table below is based on comparing actual weight to self-reported weight for women participating in a large-scale medical study. Each participant was classified into a category describing accuracy of repo
Answer Preview: There are 18 639 participants in the study and of those 12 392 reported their weigh…

, Chapter: 7 -Problem: 37 >> Exercise 7.8 gave the following probability distribution for x = the number of courses for which a randomly selected student at a certain university is registered: For this probability distribution, ? = 4.66 and ? = 1.20. a. Because ? - ? = 3.46, the x values 1, 2, and 3 are more than 1 standard deviation below the mean. What is the probability that x is more than 1 standard deviation below its
Answer Preview: a 0 02 0 03 0 09 0 14 b 2 4 66 …

, Chapter: 11 -Problem: 4 >> Use the information in the previous exercise to answer the following questions.a. Construct a 90% confidence interval estimate of the difference in mean Flesch reading ease score for health-related pages on Wikipedia and healthrelated pages on WebMD.b. What does this confidence interval imply about the readability of health-related information from these two sources? Is this consistent with the co
Answer Preview: a Check of Conditions We are told that the samples were independent and selected to be representativ…

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, Chapter: 5 -Problem: 72 >> The paper ?Depression, Body Mass Index, and Chronic Obstructive Pulmonary Disease?A Holistic Approach? (International Journal of COPD [2016]:239?249) gave data on change in body mass index (BMI in kilograms/meter2) and change in a measure of depression for patients suffering from depression who participated in a pulmonary rehabilitation program. The data in the table below are a subset of the data
Answer Preview: a The equation of the least squares regression line is y 6 873 5 078x wh…

, Chapter: 7 -Problem: 36 >> Referring to the previous exercise, use the result of Part (a) along with the fact that a carton contains 12 eggs to determine the mean value of z = the number of unbroken eggs. z can be written as a linear function of y; see Example 7.15. Previous exercise Transcribed Image Text: 3 4 y p(v) 0.65
Answer Preview: z 12 y …

, Chapter: 11 -Problem: 25 >> In Exercise 11.23, a hypothesis test leads to the conclusion that there is not convincing evidence that the mean time to exhaustion for experienced triathletes is greater when they run while listening to motivational music. Use the information given in that exercise to construct and interpret a 95% confidence interval for the difference in mean time to exhaustion for experienced triathletes when r
Answer Preview: Check of Conditions We are told to assume that it is reasonable to regard these 11 triathletes as re…

, Chapter: 5 -Problem: 24 >> Data on high school GPA (x) and first-year college GPA (y) collected from a southeastern public research university can be summarized as follows (“First-Year Academic Success: A Prediction Combining Cognitive and Psychosocial Variables for Caucasian and African American Students,” Journal of College Student Development [1999]: 599–605):a. Find the equation of the least-squares regression line.b. I
Answer Preview: To find the equation of the least-squares regression line, we can use the given data to calculate th…

, Chapter: 3 -Problem: 2 >> The graphical display on the next page is similar to one that appeared in USA TODAY (October 22, 2009). It summarizes survey responses to a question about whether visiting social networking sites is allowed at work. Which of the graph types introduced in this section is used to display the responses?
Answer Preview: Seg…

, Chapter: 9 -Problem: 44 >> The paper referenced in the previous exercise also reported that for a representative sample of 68 second-year students at the university, the sample mean procrastination score was 41.0 and the sample standard deviation was 6.82.a. Construct a 95% confidence interval estimate of m, the population mean procrastination scale for second-year students at this college.b. How does the confidence interva
Answer Preview: a Conditions 1 Since n 68 30 the sample is large enough 2 The sample w…

, Chapter: 9 -Problem: 59 >> The article ?Report: More Than Half of DC-Area Millennials Are Using Ride-Hailing Apps? (washingtonian.com/2016/06/23/report-half-dc -area-millennials-using-ride hailing-apps/, June 23, 2016, retrieved May 4, 2017) refers to a study summarizedat the following site: wbaresearch.com /wp-content/uploads/2016/06/Transportation -MarkeTrak-Spring-20161.pdf (retrieved May 4, 2017). The study indicates th
Answer Preview: a No it is not appropriate to use the large sample confidence interval for a population proportion t…

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, Chapter: 5 -Problem: 8 >> Each year J.D. Power and Associates surveys new car owners 90 days after they purchase their cars. This data is used to rate auto brands (such as Toyota and Ford) on quality and customer satisfaction. USA TODAY (usatoday.com, March 29, 2016) reported a quality rating and a satisfaction score for all 33 brands sold in the United States. a. Construct a scatterplot of y = Satisfaction rating versus
Answer Preview: a There does not appear to be a relationship between q…

, Chapter: 6 -Problem: 116 >> A theater complex is currently showing four R-rated movies, three PG-13 movies, two PG movies, and one G movie. The following table gives the number of people at the first showing of each movie on a certain Saturday: Suppose that one of these people is randomly selected. a. What is the probability that the selected individual saw a PG movie? b. What is the probability that the selected individua
Answer Preview: a 179 87 2517 0 …

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, Chapter: 5 -Problem: 40 >> Acrylamide is a chemical that is sometimes found in cooked starchy foods and which is thought to increase the risk of certain kinds of cancer. The paper “A Statistical Regression Model for the Estimation of Acrylamide Concentrations in French Fries for Excess Lifetime Cancer Risk Assessment” (Food and Chemical Toxicology [2012]: 3867–3876) describes a study to investigate the effect of x = Frying
Answer Preview: a b y 86 9 0 359x where y is the acrylamide concentration in micrograms per kilogram and x …

, Chapter: 7 -Problem: 73 >> Determine each of the following areas under the standard normal (z) curve:a. To the right of 0b. To the right of 25c. Between 21.6 and 2.5d. To the left of 0.23
Answer Preview: a 0 5 b 1 …

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, Chapter: 5 -Problem: 34 >> The California State Park System Statistical Report for the 2014/2015 Fiscal Year (parks.ca.gov/pages/795/files/14-15%20Statistical%20 Report%20-%20INTERNET.pdf) gave the accompanying data on x 5 Amount of money collected in user fees (in thousands of dollars) and y = Operating cost (in thousands of dollars) for nine state parks in the North Coast Redwoods District.User Fees (thousands of dollars)
Answer Preview: a There is a strong positive linear relationship betwe…

, Chapter: 9 -Problem: 25 >> USA TODAY reported that the proportion of Americans who prefer cheese on their burgers is 0.84 (USA TODAY, September 7, 2016). This estimate was based on a survey of a representative sample of 1000 adult Americans. Calculate and interpret a 90% confidence interval for the proportion of Americans who prefer cheese on their burgers.
Answer Preview: Check of Conditions 1 Since np 1000 0 84 840 10 and …

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, Chapter: 3 -Problem: 46 >> The report ?Daily Cigarette Use: Indicators on Children and Youth? (Child Trends Data Bank, childtrends.org/wp-content/uploads/2012/11/03 _Smoking_new.pdf, retrieved April 17, 2017) included the accompanying data on the percentage of students who report smoking cigarettes daily, for students in grades 8, 10, and 12.? a. Construct a time series plot for students in grade 12, and comment on any tre
Answer Preview: a There has been a downward trend in the percent of grade 12 students who smoke daily from …

, Chapter: 7 -Problem: 112 >> Suppose that x has a binomial distribution with n = 50 and p = 0.6, so that µ = np = 30 and ? = ?np(1 - p) = 3.464. Approximate the following probabilities using the normal approximation with the continuity correction. See Example 7.35.a. P(x = 30)b. P(x = 25)c. P(x ? 25) Distribution The word "distribution" has several meanings in the financial world, most of them pertain
Answer Preview: a b c P x 30 28 …

, Chapter: 3 -Problem: 31 >> The clearness index was determined for the skies over Baghdad for each of the 365 days during a particular year (“Contribution to the Study of the Solar Radiation Climate of the Baghdad Environment,” Solar Energy [1990]: 7–12). The accompanying table summarizes the resulting data:a. Determine the relative frequencies and draw the corresponding histogram. (Be careful here—the intervals do not all h
Answer Preview: To determine the relative frequencies, we need to calculate the proportion of each category's freque…

, Chapter: 6 -Problem: 49 >> The report ?2015 Utah Seat Belt Use Survey? (Utah Department of Public Safety?Highway Safety Office, September 14, 2015) stated that based on observing a large number of vehicle occupants, the estimated percentage of Utah drivers and passengers who wear seatbelts is 87.2%. The report also gave information on seat belt use by sex and by whether the vehicle is traveling in an urban or rural area. Th
Answer Preview: The following probabilities can be used to justify the reports …

, Chapter: 7 -Problem: 115 >> Consider the information on the MENT test given in the previous exercise.a. The exact binomial probability of a score of 42 or less for someone who is not faking the test (p = 0.96) isp(x ? 42) = 0.000000000013Explain why this probability was calculated using the binomial formula rather than using a normal approximation.b. The authors of the study described in the previous exercise propose that so
Answer Preview: a When p 0 96 n 1 p 60 0 04 2 4 which is less than 10 and so the normal approximati…

, Chapter: 10 -Problem: 63 >> The power of a test is influenced by the sample size and the choice of significance level.a. Explain how increasing the sample size affects the power (when significance level is held fixed).b. Explain how increasing the significance level affects the power (when sample size is held fixed).
Answer Preview: a Increasing the sam…

, Chapter: 6 -Problem: 55 >> A shipment of 5000 printed circuit boards contains 40 that are defective. Two boards will be chosen at random, without replacement. Consider the two events E1 = event that the first board selected is defective and E2 = event that the second board selected is defective.a. Are E1 and E2 dependent events? Explain in words.b. Let not E1 be the event that the first board selected is not defective (the
Answer Preview: a. E1 and E2 are dependent events. The dependence arises from the fact that the first board's defectiveness affects the probability of the second boar…

, Chapter: 6 -Problem: 21 >> A bookstore sells two types of books (fiction and nonfiction) in several formats (hardcover, paperback, digital, and audio). For the chance experiment that consists of observing the type and format of a single-book purchase, two of the eight possible outcomes are a hardcover fiction book and an audio nonfiction book.a. There are eight outcomes in the sample space for this experiment. List these po
Answer Preview: a The sample space is fiction hardcover fiction p…

, Chapter: 6 -Problem: 76 >> Refer to the information given in the previous exercise about customers of a large cable company.a. Suppose two customers are to be selected at random. Would it be reasonable to consider the events C1 = event that the first customer selected subscribes to cable TV and C2 = event that the second customer selected subscribes to cable TV as independent events? Explain.b. With C1 and C2 as defined in
Answer Preview: a Yes Since it is a large cable company me…

, Chapter: 11 -Problem: 30 >> The paper referenced in the previous exercise also had the 50 taxi drivers drive in the simulator while sending and receiving text messages. The mean of the 50 sample differences (no distraction – reading text messages) was 1.3 meters and the standard deviation of the sample differences was 1.54 meters. The authors concluded that there was evidence to support the claim that the mean following dist
Answer Preview: 1 d mean difference in the paired means no distraction reading text …

, Chapter: 5 -Problem: 69 >> The paper “Root Dentine Transparency: Age Determination of Human Teeth Using Computerized Densitometric Analysis” (American Journal of Physical Anthropology [1991]: 25–30) reported on an investigation of methods for age determination based on tooth characteristics. With y = age (in years) and x = percentage of root with transparent dentine, a regression analysis for premolars gave n = 36, SSResid
Answer Preview: To calculate the values of r^2 and se (standard error), we need to use the provided information from …

, Chapter: 3 -Problem: 63 >> The National Center for Education Statistics reported the following data on the average cost per year for tuition, fees, and room and board for 4-year public institutions in the United States (nces.ed .gov/fastfacts/display.asp?id=76, retrieved April 17, 2017). Construct a time series plot of these data and comment on the trend over time. Year............................Average Cost 2002..........
Answer Preview: There is a strong positive trend in the average cost of per year for tuit…

, Chapter: 9 -Problem: 27 >> Business Insider reported that a study commissioned by eBay motors found that nearly 40% of millennials who drive a car that is more than 5 years old have named their cars (“Millennials Have an Odd Habit When It Comes to Their Cars,” April 14, 2016). Suppose that this statement was based on a sample of size 800 and that 312 reported that they had named their car. Assuming that the sample was selec
Answer Preview: Check of Conditions 1 Since np 800 312 800 312 10 and n 1 p …

, Chapter: 11 -Problem: 6 >> The National Sleep Foundation surveyed representative samples of adults in six different countries to ask questions about sleeping habits (“2013 International Bedroom Poll Summary of Findings,” sleepfoundation.org/sites/default/files/RPT495a .pdf). Each person in a representative sample of 250 adults in each of these countries was asked how much sleep they get on a typical work night. For the Unit
Answer Preview: 1 1 mean number of minutes of sleep adults in Mexico get on a ty…

, Chapter: 6 -Problem: 60 >> A construction firm bids on two different contracts. Let E1 be the event that the bid on the first contract is successful, and define E2 analogously for the second contract. Suppose that P(E1) = .4 and P(E2) = .2 and that E1 and E2 are independent events.a. Calculate the probability that both bids are successful (the probability of the event E1 and E2).b. Calculate the probability that neither bid
Answer Preview: To solve these problems, we can use the fact that the events E1 and E2 are independent. This means t…

, Chapter: 4 -Problem: 23 >> The price (in dollars) of the eight smart phones that were rated highest by Consumer Reports in 2018 (consumerreports.org, retrieved February 23, 2018) were 730 850 830 800 700 1000 950 520 a. Calculate the values of the variance and the standard deviation. b. The standard deviation is quite large. What does that tell you about the prices of these highly-rated smartphones?
Answer Preview: a b The large value of the standard deviation t…

, Chapter: 9 -Problem: 46 >> The authors of the paper “Driving Performance While Using a Mobile Phone: A Simulation Study of Greek Professional Drivers” (Transportation Research Part F [2016]: 164–170) describe a study to evaluate the effect of mobile phone use by taxi drivers in Greece. Fifty taxi drivers drove in a driving simu

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