Stats Modeling The World 6th Edition Richard De Veaux, Paul Velleman, David Bock, Floyd Bullard - Solutions

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Although the event may seem startling to their students, 119 Statistics teachers participated in a fun run. Before the run, each person was asked to guess what their time would be (in seconds). After the run, the actual times were plotted against the teachers’ guesses, and the assumptions for
Some states are moving to eliminate the sale of gas-powered cars and only allowing the sales of electric cars. While some citizens are excited at the prospect of a world with only electric cars, other people have an attachment to the type of cars they grew up with. Here is a survey, conducted using
A study published in 2005 examined health and diet among a representative sample of Canadian women. Researchers reported that only 6.8% of women who were vegetarians had high cholesterol, compared to 11.3% of nonvegetarians.a) Explain two reasons why this study would not justify a newspaper
Jane’s Java serves both coffee and tea, each in a small or large size. History shows that 70% of the customers who order just one drink order coffee. Of those customers, 80% order a large;60% of the customers who order tea order a large.a) Compute the probability that a random customer who orders
A small town has a Farmer’s Market each Thursday night in a downtown park. Local growers, as well as craft makers and food vendors, set up booths for three hours. The Chamber of Commerce believes that the Market helps other downtown businesses because it attracts more visitors to the area.
Origami USA hosts a conference in New York City every summer. Classes are offered on beginner, intermediate, and advanced levels of folding. Simple paper models use only a few folds, while the more complex models require more folds. The boxplot and statistics summarize the number of folds required
Researchers are conducting an experiment at a zoo to compare the effect of two food supplements on weight gain among meerkats. The zoo has a large population of meerkats that live in 8 groups, each with separate living areas. Researchers will randomly assign four of the living areas to receive each
To make a decision about closing time, a fast-food restaurant has recorded data on the number of customers using its drivethrough window between 10:00 and 11:00 p.m. on Sunday through Thursday. A summary is shown in the table What is the interquartile range for these data?A) 3 B) 4 C) 5 D) 6 E) 7
A supplier tells a large hospital stockroom that the facility should buy 30% small, 45% medium, and 25% large surgical gloves. When the stockroom manager randomly surveys 110 workers about their size preferences, 23 request small, 57 medium, and 30 large gloves. The manager wonders whether this
To study the effectiveness of an interactive e-book, a researcher gave 20 students a pretest, had them study from The researcher conducted a hypothesis test to see if using the e-book would produce a significant increase in mean score.What P-value did they find?A) 0.028 B) 0.087 C) 0.091 D) 0.094
A researcher looks for a linear relationship between increasing the dosage of a vaccine the presence of antibodies. A scatterplot shows a weak linear relationship and the P-value for the slope is 0.349. Which of these is an appropriate conclusion?A) With statistically significant evidence, more
A study conducted in 2007 by the Baylor Department of Sociology asked the following question: “Please indicate your level of agreement with the following statement about science: Humans evolved from other primates over millions of years.” The researcher summarized the data in a table
Factory supervisors conducting a quality control study sampled twenty production batches and recorded the number of items in each sample that failed to meet standards. The results are summarized in the cumulative relative frequency histogram below.What is the probability that a sample had exactly
The salmon filets a seafood shop buys from a supplier weigh an average of 5.6 ounces, but 12% of them weigh less than 4 ounces. The shop owner believes the weights are normally distributed. What’s the standard deviation of the filet weights?A) 0.73 oz B) 1.03 oz C) 1.17 oz D) 1.36 oz E) 3.40 oz
For a Statistics class project at a large high school, a senior asked a random sample of students how often they use social networking sites. The relative frequencies of responses by male and female students are displayed in the bar chart below.Which of the following statements can be supported by
In a symmetric distribution, which of the following should be true?I. Maximum value Median Median Minimum value −≈−II. Q3 Median Median Q1 −≈−III. Maximum value Q3 Q1 Minimum value −≈−A) I only B) II only C) III only D) II and III only E) I, II, and III
The regression analysis below models the relationship between the fuel efficiency (in miles per gallon) and horsepower (in 100’s) for a random sample of 15 cars.Dependent variable is: MPG R-squared 82.6% R-s = = quared adjusted ( ) 81.3%s 2.435 = with 15 2 13 − = degrees of freedom Variable
An investigation of water plant growth compares the heights(in inches) of a species of plant growing in two different lakes.The null hypothesis is H01 2 : . μ μ = Here are the summaries of the data collected What are the mean and standard error of the sampling distribution for the difference in
Logs to be sawed into boards are first rough-cut to be a bit over 8 feet long. Measurements found the actual mean length to be 98.5 inches and 20% of the logs were longer than 100 inches. Assuming the logs’ lengths are normally distributed, approximately what percentage of such logs should be
The Pew Research Center asked a random sample of 1047 adult(aged 18+) social media users and 623 teen (aged 12–17) social media users the following question: “How often do you witness online cruelty and meanness?” The table below summarizes the responses Pew obtained.To test for differences
Which sample result would provide evidence that there is an association between two quantitative variables based on a hypothesis test for the true population slope β1?A) Any sample with b1 = 0 B) Any sample with b1 ≠ 0 C) Any sample with b1 > 0 D) Any sample with b1 significantly close to 0 E)
One advantage of using a control group with a placebo in an experiment is that the experiment will be A) better because of the larger number of treatment groups.B) better able to account for variability arising from extraneous factors.
A zoologist studying a certain species of rats investigated the relationship between the weights of adult rats (in grams) and the lengths of their tails (in centimeters). The regression analysis for his data is shown below.Response variable: Weight Variable Coef Std Error t-ratio P-value Constant
A citrus grower offers gourmet gift boxes of 6 Ruby Red grapefruits. The grapefruits used in these boxes weigh an average of 18 ounces with a standard deviation of 1.2 ounces. Assuming the weights are approximately normally distributed, what is the probability that the average weight of the Ruby
In 2003 the U.S. Department of Education conducted a National Assessment of Adult Literacy by interviewing a random sample of 18,102 adults (aged 16 ). Researchers assessed the respon- +dents’ literacy levels and also asked them how often they engaged in volunteer activities. The data are
A company selling home furnaces claims that installing its new high efficiency furnace will “cut your heating bill in half.” A consumer agency collects data for a random sample of homes and plots this year’s heating costs with the new furnaces against
Maria has data from a random sample of 16 subjects and is constructing a 95% confidence interval for the population mean.Which value should she use for t*?A) 1.746 B) 1.753 C) 1.960 D) 2.120 E) 2.131
A researcher discovered a data error that led her to eliminate the outlier seen in the lower left of her original scatterplot below.What effect did removing that point have on the slope of the regression line and the value of R2 she had previously calculated?A) The slope decreased and R2
Some pet shop owners will soon begin selling a new variety of turtle, but first they want to determine the best environment for raising them. They want to try three aquarium temperatures and two different mixtures of food. They will randomly assign the different combinations of temperature and food
Could listening to rock music raise your blood pressure? To find out, researchers randomly divided 50 subjects into two groups. For 10 minutes, people in one group listened to loud rock music and those in the other group listened to soft jazz.The researchers recorded each person’s change in blood
The PSA is a screening test for prostate cancer often recommended for men over 50. Unfortunately, it’s not very reliable.Further testing reveals that only 30% of the men whose PSA comes back positive actually do have prostate cancer. Suppose a lab processing several PSAs reports 8 positive
Which is the appropriate interpretation of the slope of the bacterial growth model in Question 14 above?A) For every additional 0.61 hours of growth, the culture is predicted to weigh 1 more gram.B) For every additional hour of growth, the culture is predicted to weigh 0.61 more grams.C) For every
An analysis of laboratory data collected with the goal of modeling the weight (in grams) of a bacterial culture after several hours of growth produced the least squares regression line l og( ) 0.25 0.61 . Weight Hours = + Estimate the weight of the culture after 3 hours.A) 0.32 g B) 2.08 g C) 8.0 g
In June 2012 the Gallup organization conducted a poll using a random sample of 1004 adults, aged 18 and older, living in all 50 U.S. states and the District of Columbia. When asked, “On the whole, do you think immigration is a good thing or a bad thing for this country?” 66% responded “a good
Among the seniors at a certain high school, 65% attended the prom and 45% went on the senior trip, but 25% of the seniors did not participate in either the prom or the trip. What’s the probability that a senior who went on the trip attended the prom?A) 0.20 B) 0.35 C) 0.54 D) 0.69 E) 0.78
Soda companies have begun marketing 10-calorie sodas. The companies believe men prefer the taste and name of these drinks over traditional diet sodas. The table below summarizes preferences expressed by a random sample of 50 men and 50 women and also shows expected cell counts in parentheses.In
Which of the following statements is true?A) A P-value of 0.011 is weaker evidence against the null hypothesis than a P-value of 0.033.B) If we reject the null hypothesis at α = 0.05, we’d also reject it at α = 0.01.C) We can increase the power of a test by decreasing the significance level
The table shows the probability distribution for the number of points (X) a player can win by spinning a child’s game spinner.If every point won moves you 5 spaces closer to winning, what is the average number of spaces moved per spin?
What is the smallest number of babies that must be randomly selected and tested in order to estimate the rate of jaundice among newborns to within ±3% with 95% confidence?A) 250 B) 500 C) 800 D) 1200 E) 1500
A consumer group doing marketing research on consumer preferences for soft drinks will conduct a taste test comparing cola C and cola P. Which of the following is not a good suggestion for an effective study?A) Include people of different ages, genders, and other characteristics.B) Randomly select
In Las Vegas $1 slot machines average a 95% payout; in other words, the expected value of a $1 bet is $0.95. Given that the machines’ outcomes are random, which of these is true?A) A gambler who spends $100 will win $95 back.B) If a gambler plays long enough, they’ll get all but 5% of his money
A school district will use grade 1–5 students at one elementary school to study whether a new reading program can produce better reading comprehension scores. Half of the students will continue with the current program, and half will receive instruction with the new program. Which is the most
The price of video games often starts high when initial demand is high and then decreases as time goes on. A scatterplot of data collected for a sample of games suggests a linear model is reasonable, and an analysis produced a correlation coefficient of−0.78. What percent of the variation in
Researchers are investigating the association between the temperature in degrees and sales of hot dogs (in hundreds) at an outdoor sports stadium for a random sample of days. They constructed a 95% confidence interval for the slope of the regression line for predicting Sales from Temperature,
What’s the standard deviation of the number of women found in samples of college students like the one described in Question 1 above?A) 2.49 B) 3.16 C) 4.43 D) 4.47 E) 6.21
In a large university, 56% of the undergraduate students are female, as are 42% of the graduate students. How many females would we expect there to be in a random sample of 50 undergraduate and 30 graduate students?A) 18.8 B) 19.6 C) 37.8 D) 39.2 E) 40.6
Eat kale? The Vegan Club on campus is curious about using documentaries to inform students about healthy foods. To begin, members of the club poll a few classmates and find that 3 out of 15 students are willing to eat a kale salad. Then they show the documentary Forks over Knives to a different
Sleepy An AP U.S. History teacher is worried that their first period class is sleepy when they take their exams. They decide to compare the scores from their first period to their second period class. Here are their scores:a) Which inference procedure is appropriate?b) The teacher calculates the
Family planning A 1954 study of 1438 pregnant women examined the association between the woman’s education level and the occurrence of unplanned pregnancies, producing these data:Do these data provide evidence of an association between family planning and education in this era? (Fertility
Seat belts 2015 The National Highway Traffic Safety Administration reported seat belt use and fatalities in car accidents.(Seat Belt Use in 2015—Use Rates in the States and Territories. Report no. DOT HS-812-274) Is the rate of seat belt use different in New England compared to the Mountain
More errors A corporation with a fleet of vehicles wanted to test the cost-effectiveness of using Motor Silk oil additive. For the study, 6100 delivery and passenger vehicles were tested for the same 3-month period in one year and then again in the subsequent year. In the initial year, the fleet
Free throws 2017 At the middle of the 2016–2017 NBA season, James Hardin led the league by making 468 of 544 free throws, for a success rate of 86%. But Russell Westbrook was close behind with 425 of 517 (82.2% .)a) Find a 95% confidence interval for the difference in their free throw
Cramming Students in two basic Spanish classes were required to learn 50 new vocabulary words. One group of 45 students received the list on Monday and studied the words all week.Statistics summarizing this group’s scores on Friday’s quiz are given. The other group of 25 students did not get
Diet Thirteen overweight women volunteered for a study to determine whether eating specially prepared crackers before a meal could help them lose weight. The subjects were randomly assigned to eat crackers with different types of fiber (bran fiber, gum fiber, both, and a control cracker).
Education vs. income The following displays examine the median income and education level (years in school) for several U.S. cities:a) Do you think the assumptions for inference are met? Explain.b) Does there appear to be an association between education and income levels in these cities?c) Would
Weight loss A weight loss clinic advertises that its program of diet and exercise will allow clients to lose 10 pounds in one month.A local reporter investigating weight reduction gets permission to interview a randomly selected sample of clients who report the given weight losses during their
Infliximab In an article appearing in the journal The Lancet in 2002, medical researchers reported on the experimental use of the arthritis drug infliximab in treating Crohn’s disease. In a trial, 573 patients were given initial 5-mg injections of the drug.Two weeks later, 335 had responded
Dairy sales Peninsula Creameries sells both cottage cheese and ice cream. The CEO recently noticed that in months when the company sells more cottage cheese, it seems to sell more ice cream as well. Two of his aides were assigned to test whether this is true or not. The first aide’s plot and
Pesticides A study published in 2002 in the journal Environmental Health Perspectives examined the gender ratios of children born to workers exposed to dioxin in Russian pesticide factories. The data covered the years from 1961 to 1988 in the city of Ufa, Bashkortostan, Russia. Of 227 children born
Learning math Developers of a new math curriculum called“Accelerated Math” compared performances of students taught by their system with control groups of students in the same schools who were taught using traditional instructional methods and materials. Statistics about pretest and posttest
Togetherness Are good grades in high school associated with family togetherness? A simple random sample of 142 highschool students was asked how many meals per week their families ate together. Their responses produced a mean of 3.78 meals per week, with a standard deviation of 2.2. Researchers
Old Faithful As you saw in an earlier chapter, Old Faithful isn’t all that faithful. Eruptions do not occur at uniform intervals and may vary greatly. Can we improve our chances of predicting the time of the next eruption if we know how long the previous eruption lasted?a) Describe what you see
Eating in front of the TV Roper Reports asked a random sample of people in 30 countries whether they agreed with the statement “I like to nibble while reading or watching TV.”Allowable responses were “Agree Completely,” “Agree Somewhat,” “Neither Disagree Nor Agree,” “Disagree
Pregnancy In 1998 a San Diego reproductive clinic reported 42 live births to 157 women under the age of 38, but only 7 live births for 89 clients aged 38 and older. Is this evidence of a difference in the effectiveness of the clinic’s methods for older women?a) Test the appropriate hypotheses
Depression and the Internet The September 1998 issue of the American Psychologist published an article reporting on an experiment examining “the social and psychological impact of the Internet on 162 people in 73 households during their first 1 to 2 years online.” In the experiment, a sample of
Eye and hair color A survey of 1021 school-age children was conducted by randomly selecting children from several large urban elementary schools. Two of the questions concerned eye and hair color. In the survey, the following codes were used: The Statistics students analyzing the data were asked to
Wealth redistribution 2015 The following table is based on a Gallup Poll of 3045 U.S. adults on April 9–12, 2015. Respondents were stratified as high income (over $75,000), middle income ($30,000–$75,000), or low income (less than $30,000).Those polled were asked for their views on
Birth days During a 2-month period, 72 babies were born at the Tompkins Community Hospital in upstate New York. The table shows how many babies were born on each day of the week.a) If births are uniformly distributed across all days of the week, how many would you expect on each day?b) Test the
Age and party 2019 The Pew Research Center conducted representative telephone surveys in 2018 and 2019. The following table shows the preferred political party affiliation of respondents and their ages for a sample of 1003 voters. Is there evidence of age-based differences in party affiliation in
LA rainfall The Los Angeles Almanac website reports recent annual rainfall (in inches), as shown in the tablea) Create a 90% confidence interval for the mean annual rainfall in LA.b) Do these data suggest any change in annual rainfall as time passes? Check for an association between rainfall and
Preemies Do the effects of being born prematurely linger into adulthood? Researchers examined 242 Cleveland-area children born prematurely between 1977 and 1979, and compared them with 233 children of normal birth weight; 24 of the “preemies”and 12 of the other children were described as being
Twins, again After reading of the JAMA study in Exercise 12, a large city hospital examined its records of twin births for several years and found the data summarized in the table below. Is there evidence that the way the hospital deals with pregnancies involving twins may have changed?
Twins In 2000 the Journal of the American Medical Association published a study that examined a sample of pregnancies that resulted in the birth of twins. Births were classified as preterm with intervention (induced labor or cesarean), preterm without such procedures, or term or post-term.
Polling How accurate are pollsters in predicting the outcomes of congressional elections? The table shows the actual number of Democratic party seats in the House of Representatives and the number predicted by the Gallup organization for nonpresidential election years between World War II and
AP Statistics scores 2016 In 2016, about 200,000 Statistics students nationwide took the Advanced Placement Examination in Statistics. The national distribution of scores and the results at Ithaca High School are shown in the table.Is the distribution of scores at this high school significantly
Lefties and music In an experiment to see if left- and right-handed people have different abilities in music, subjects heard a tone and were then asked to identify which of several other tones matched the first. Of 76 right-handed subjects, 38 were successful in completing this test, compared with
Wild horses Large herds of wild horses can become a problem on some federal lands in the West. Researchers hoping to improve the management of these herds collected data to see if they could predict the number of foals that would be born based on the size of the current herd. Their attempt to model
Economic inequity 2020 The following table is based on a Pew Research Poll of 6593 U.S. adults in January 2020.Respondents were classified as high income (over $120,400), middle income ($40,100–$120,400), or low income (less than$40,100). Those polled were asked for their views on choosing one
Paper airplanes In preparation for a regional paper airplane competition, a student tried out her latest design. The distances her plane traveled (in feet) in 11 trial flights are given here.(The world record is an astounding 193.01 feet!) The data were 62, 52, 68, 23, 34, 45, 27, 42, 83, 56, and
Resume fraud In 2002 the Veritas Software company found out that its chief financial officer did not actually have the MBA he had listed on his resume. They fired him, and the value of the company’s stock dropped 19%. Kroll, Inc., a firm that specializes in investigating such matters, said that
Mutual funds In July 2011, the Wall Street Journal Online reported the rate of return for the top 20 large-cap mutual funds over the last 10 years. (“Large cap” refers to companies worth over $10 billion.) Among other results, the Journal listed the 3-year and 5-year returns. (online.wsj.com)a)
Hard water In an investigation of environmental causes of disease, data were collected on the annual mortality rate (deaths per 100,000) for males in 61 large towns in England and Wales.In addition, the water hardness was recorded as the calcium concentration (parts per million, or ppm) in the
Tableware Nambe Mills manufactures plates, bowls, and other tableware made from an alloy of several metals. Each item must go through several steps, including polishing. To better understand the production process and its impact on pricing, the company checked the polishing time (in minutes) and
Genetics Two human traits controlled by a single gene are the ability to roll one’s tongue and whether one’s ear lobes are free or attached to the neck. Genetic theory says that people will have neither, one, or both of these traits in the ratio 1:3:3:9(1 attached, noncurling; 3 attached,
Property assessments The software outputs below provide information about the Size (in square feet) of 18 homes in Ithaca, New York, and the city’s assessed Value of those homes.oooooooooooooa) Explain why inference for linear regression is appropriate with these data.b) Is there a significant
Education and mortality The software output below is based on the mortality rate (deaths per 100,000 people) and the education level (average number of years in school) for 58 U.S. cities.a) Comment on the assumptions for inference.b) Is there evidence of a strong association between the level of
All the efficiency money can buy 2011 A sample of 84 model-2011 cars from an online information service was examined to see how fuel efficiency (as highway mpg) relates to the cost (Manufacturer’s Suggested Retail Price in dollars) of cars.Here are displays and computer output:a) State what you
Strike two Remember the Little League instructional video discussed in Chapter 24? Ads claimed it would improve the performances of Little League pitchers. To test this claim, 20 Little Leaguers threw 50 pitches each, and we recorded the number of strikes. After the players participated in the
Still more roller coasters Of the 91 “Thrill” roller coasters that were described in Exercise 28, data were available on the durations of 65 of them. A scatterplot of their durations against their heights showed no unusual features that would suggest that a linear model is inappropriate.
More roller coasters Some roller coasters that are unusually fast or have special features are classified as “extreme” by aficionados. There were 190 such coasters operating in the Unites States at the end of 2020, according to the web site rcdb.com. A scatterplot of their lengths and their
Body fat, again Use the data from Exercise 45 to examine the association between Weight Size and % Body Fat.a) Find a 90% confidence interval for the slope of the regression line of % Body Fat on Weight Size.b) Interpret your interval in context.
Body fat Do the data shown in the table below indicate an association between Waist Size and % Body Fat? Test an appropriate hypothesis and state your conclusion.
Crawling Researchers at the University of Denver Infant Study Center wondered whether temperature might influence the age at which babies learn to crawl. Perhaps the extra clothing that babies wear in cold weather would restrict movement and delay the age at which they started crawling. Data were
Tablet computers CNET.com tests tablet computers and continuously updates its list. As of October 2020, the list included the battery life (in hours) and luminous intensity(i.e., screen brightness, in cd m2 ). We want to know if Battery life is related to the maximum Screen
More sales and profits Consider again the relationship between the sales and profits of Fortune 500 companies that you analyzed in Exercise 38.Find a 95% confidence interval for the slope of the regression line. Interpret your interval in context.
Ozone, again Consider again the relationship between the population and ozone level of U.S. cities that you analyzed in Exercise 37.Give a 90% confidence interval for the approximate increase in ozone level associated with each additional million city inhabitants.
Sales and profits A business analyst was interested in the relationship between a company’s sales and its profits. They collected data (in millions of dollars) from a random sample of Fortune 500 companies and created the regression analysis and summary statistics shown. The assumptions for
Ozone The Environmental Protection Agency is examining the relationship between the ozone level (in parts per million) and the population (in millions) of U.S. cities. Part of the regression analysis is shown.a) We suspect that the greater the population of a city, the higher its ozone level. Is
SAT scores How strong was the association between student scores on the Math and Verbal sections of the old SAT? Scores on each ranged from 200 to 800 and were widely used by college admissions offices. Here are summaries and plots of the scores for a graduating class at Ithaca High School:a) Is
Acid rain Biologists studying the effects of acid rain on wildlife collected data from 163 streams in the Adirondack Mountains. They recorded the pH (acidity) of the water and the BCI, a measure of biological diversity. Here’s a scatterplot of BCI against pH:a) State the null and alternative

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Stats Modeling The World 6th Edition Richard De Veaux, Paul Velleman, David Bock, Floyd Bullard - Solutions

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