The Practice Of Statistics 6th Edition Daren S. Starnes, Josh Tabor - Solutions

Do drivers take longer to leave their parking spaces when someone is waiting? Researchers hung out in a parking lot and collected some data. The graphs and numerical summaries display information about how long it took drivers to exit their spaces.a. Write a few sentences comparing these
To find out what proportion of Americans support proposed Medicare legislation to help pay medical costs, the AARP conducted a survey of their members (people over age 50 who pay membership dues). One of the questions was: “Even if this plan won’t affect you personally either way, do you think
Ten percent of U.S. households contain 5 or more people. You want to simulate choosing a household at random and recording “Yes” if it contains 5 or more people. Which of these is a correct assignment of digits for this simulation?a. Odd = Yes; Even = Nob. 0 = Yes; 1–9 = Noc. 0−5 = Yes;
Suppose this player attempts 10 shots in a game and makes only 3 of them. Does this provide convincing evidence that she is less than a 47% shooter?a. Yes, because 3/10 (30%) is less than 47%.b. Yes, because she never made 47% of her shots in the simulation.c. No, because it is plausible
A total of 25 repetitions of the simulation were performed. The number of makes in each set of 10 simulated shots was recorded on the dotplot. What is the approximate probability that a 47% shooter makes 5 or more shots in 10 attempts?a. 5/10b. 3/10c. 12/25d. 3/25e. 47/100A basketball player claims
If I toss a fair coin five times and the outcomes are TTTTT, then the probability that tails appears on the next toss isa. 0.5.b. less than 0.5.c. greater than 0.5.d. 0.e. 1.Select the best answer.
To simulate the number of makes in 10 shot attempts, you would perform the simulation as follows:a. Use 10 random one-digit numbers, where 0–4 are a make and 5– 9 are a miss.b. Use 10 random two-digit numbers, where 00–46 are a make and 47–99 are a miss.c. Use 10 random two-digit numbers,
A recent study reported that fewer than half of young adults turn off the water while brushing their teeth. Is the same true for teenagers? To find out, a group of statistics students asked an SRS of 60 students at their school if they usually brush with the water off. In the sample, 27 students
You read in a book about bridge that the probability that each of the four players is dealt exactly one ace is approximately 0.11. This means thata. in every 100 bridge deals, each player has 1 ace exactly 11 times.b. in 1 million bridge deals, the number of deals on which each player has 1 ace
About 7% of men in the United States have some form of red–green color blindness. Suppose we randomly select one U.S. adult male at a time until we find one who is red–green colorblind. Should we be surprised if it takes us 20 or more men? Describe how you would carry out a simulation to
Do most teens recycle? To find out, an AP® Statistics class asked an SRS of 100 students at their school whether they regularly recycle. In the sample, 55 students said that they recycle. Is this convincing evidence that more than half of the students at the school would say they regularly
Every 9 weeks, Mr. Millar collects students’ notebooks and checks their homework. He randomly selects 4 different assignments to inspect for all of the students. Marino is one of the students in Mr. Millar’s class. Marino completed 20 homework assignments and did not complete 10 assignments. He
A website claims that 10% of U.S. adults are left-handed. A researcher believes that this figure is too low. She decides to test this claim by taking a random sample of 20 U.S. adults and recording how many are left-handed. Four of the adults in the sample are left-handed. Does this result give
According to New Jersey Transit, the 8:00 A.M. weekday train from Princeton to New York City has a 90% chance of arriving on time. To test this claim, an auditor chooses 6 weekdays at random during a month to ride this train. The train arrives late on 2 of those days. Does the auditor have
Researchers recruited 20 volunteers—8 men and 12 women—to take part in an experiment. They randomly assigned the subjects into two groups of 10 people each. To their surprise, 6 of the 8 men were randomly assigned to the same treatment. Should they be surprised? We want to design a simulation
In the game of Scrabble, each player begins by randomly selecting 7 tiles from a bag containing 100 tiles. There are 42 vowels, 56 consonants, and 2 blank tiles in the bag. Cait chooses her 7 tiles and is surprised to discover that all of them are vowels. We want to perform a simulation to
A media report claims that 50% of U.S. teens with smartphones feel addicted to their devices.3 A skeptical researcher believes that this figure is too high. She decides to test the claim by taking a random sample of 100 U.S. teens who have smartphones. Only 40 of the teens in the sample feel
At the end of basketball practice, each player on the team must shoot free throws until he makes 10 of them. Dwayne is a 70% free-throw shooter. That is, his probability of making any free throw is 0.70. We want to design a simulation to estimate the probability that Dwayne makes 10 free throws in
The Transportation Security Administration (TSA) is responsible for airport safety. On some flights, TSA officers randomly select passengers for an extra security check prior to boarding. One such flight had 76 passengers —12 in first class and 64 in coach class. Some passengers were surprised
A professional tennis player claims to get 90% of her second serves in. In a recent match, the player missed 5 of her first 20 second serves. Is this a surprising result if the player’s claim is true? Assume that the player has a 0.10 probability of missing each second serve. We want to carry out
Luke’s teacher has assigned each student in his class an online quiz, which is made up of 10 multiple-choice questions with 4 options each. Luke hasn’t been paying attention in class and has to guess on each question. However, his teacher allows each student to take the quiz three times and
A very good professional baseball player gets a hit about 35% of the time over an entire season. After the player failed to hit safely in six straight at-bats, a TV commentator said, “He is due for a hit.” Explain why the commentator is wrong.
a. A gambler knows that red and black are equally likely to occur on each spin of a roulette wheel. He observes that 5 consecutive reds have occurred and bets heavily on black at the next spin. Asked why, he explains that “black is due.” Explain to the gambler what is wrong with this
The figure shows the results of two different sets of 5000 coin tosses. Explain what this graph tells you about chance behavior in the short run and the long run. 1.0 0.9 - 0.8 - 0.7 - 0.6 - 0.5 0.4 - 0.3 - 0.2 - 0.1 - 0.0 1 5000 Number of tosses Proportion of heads
The figure shows the results of a basketball player attempting many 3 point shots. Explain what this graph tells you about chance behavior in the short run and long run. 100 50 1000 Number of shots Percent made
Many women choose to have annual mammograms to screen for breast cancer after age 40. A mammogram isn’t foolproof. Sometimes the test suggests that a woman has breast cancer when she really doesn’t (a “false positive”). Other times the test says that a woman doesn’t have breast cancer
Sometimes police use a lie detector test to help determine whether a suspect is telling the truth. A lie detector test isn’t foolproof sometimes it suggests that a person is lying when he or she is actually telling the truth (a “false positive”). Other times, the test says that the suspect is
There are many married couples in which the husband and wife both carry a gene for cystic fibrosis but don’t have the disease themselves. Suppose we select one of these couples at random. According to the laws of genetics, the probability that their first child will develop cystic fibrosis is
If Aaron tunes into his favorite radio station at a randomly selected time, there is a 0.20 probability that a commercial will be playing.a. Interpret this probability as a long-run relative frequency.b. If Aaron tunes into this station at 5 randomly selected times, will there be exactly one time
The business magazine Forbes reports that 4567 companies sold their first stock to the public between 1990 and 2000. The mean change in the stock price of these companies since the first stock was issued was +111%. The median change was −31%. Explain how this difference could happen.
“It is right to use animals for medical testing if it might save human lives.” The General Social Survey asked 1152 adults to react to this statement. Here is the two-way table of their responses:a. Construct segmented bar graphs to display the distribution of opinion for males and for
Do product labels influence customer perceptions? To find out, researchers recruited more than 500 adults and asked them to estimate the number of calories, amount of added sugar, and amount of fat in a variety of food products. Half of the subjects were randomly assigned to evaluate products with
Some news organizations maintain a database of customers who have volunteered to share their opinions on a variety of issues. Suppose that one of these databases includes 9000 registered voters in California. To measure the amount of support for a controversial ballot issue, 1000 registered voters
Researchers on aging proposed to investigate the effect of supplemental health services on the quality of life of older people. Eligible patients on the rolls of a large medical clinic were to be randomly assigned to treatment and control groups. The treatment group would be offered hearing aids,
Texas A&M, like many universities, offers screening for HIV, the virus that causes AIDS. Students may choose either anonymous or confidential screening. An announcement says, “Persons who sign up for screening will be assigned a number so that they do not have to give their name.” They can
In the 1960s, children entering the Willowbrook State School, an institution for the intellectually disabled on Staten Island in New York, were deliberately infected with hepatitis. The researchers argued that almost all children in the institution quickly became infected anyway. The studies showed
One of the most important nongovernment surveys in the United States is the National Opinion Research Center’s General Social Survey (GSS). The GSS regularly monitors public opinion on a wide variety of political and social issues. Interviews are conducted in person in the subject’s home. Are a
In which of the circumstances listed here would you allow collecting personal information without the subjects’ consent?a. A government agency takes a random sample of income tax returns to obtain information on the average income of people in different occupations. Only the incomes and
In cooperation with researchers from Cornell University, Facebook randomly selected almost 700,000 users for an experiment in “emotional contagion.” Users’ news feeds were manipulated (without their knowledge) to selectively show postings from their friends that were either more positive or
Government regulations require that institutional review boards consist of at least five people, including at least one scientist, one nonscientist, and one person from outside the institution. Most boards are larger, but many contain just one outsider.a. Why should review boards contain people who
You have been invited to serve on a college’s institutional review board. You must decide whether several research proposals qualify for lighter review because they involve only minimal risk to subjects. Federal regulations say that “minimal risk” means the risks are no greater than “those
A study of strength training and memory randomly assigned 46 young adults to two groups. After both groups were shown 90 pictures, one group had to bend and extend one leg against heavy resistance 60 times. The other group stayed relaxed, while the researchers used the same exercise machine to bend
Eating blueberries and strawberries might improve heart health, according to a long-term study of 93,600 women who volunteered to take part. These berries are high in anthocyanins due to their pigment. Women who reported consuming the most anthocyanins had a significantly smaller risk of heart
Is a friendly surgeon a better surgeon? In a study of more than 32,000 surgical patients from 7 different medical centers, researchers classified surgeons by the number of unsolicited complaints that had been recorded about their behavior. The researchers found that surgical complications were
One of the better studies of the effect of regular attendance at religious services gathered data from a random sample of 3617 adults. The researchers then measured lots of variables, not just the explanatory variable (religious activities) and the response variable (length of life). A news article
Will storing batteries in a freezer make them last longer? To find out, a company that produces batteries takes a random sample of 100 AA batteries from its warehouse. The company statistician randomly assigns 50 batteries to be stored in the freezer and the other 50 to be stored at room
Do abandoned children placed in foster homes do better than similar children placed in an institution? The Bucharest Early Intervention Project found statistically significant evidence that they do. The subjects were 136 young children abandoned at birth and living in orphanages in Bucharest,
A study published in the New England Journal of Medicine compared two medicines to treat head lice: an oral medication called ivermectin and a topical lotion containing malathion. Researchers studied 812 people in 376 households in seven areas around the world. Of the 185 households randomly
Dr. Linda Stern and her colleagues recruited 132 obese adults at the Philadelphia Veterans Affairs Medical Center in Pennsylvania. Half the participants were randomly assigned to a low-carbohydrate diet and the other half to a low-fat diet. Researchers measured each participant’s change in weight
Are people influenced by what others say? Michael conducted an experiment in front of a popular gym. As people entered, he asked them how many days they typically work out per week. As he asked the question, he showed the subjects one of two clipboards, determined at random. Clipboard A had the
Over the years, the percentage of births that are planned caesarean sections has been rising. Because doctors can schedule these deliveries, there might be more children born during the week and fewer born on the weekend than if births were uniformly distributed throughout the week. To investigate,
According to a newspaper article, “Most people are kissing the ‘right way.’” That is, according to a study, the majority of couples prefer to tilt their heads to the right when kissing. In the study, a researcher observed a random sample of 124 kissing couples and found that 83/124 (66.9%)
Using a webcam, a traffic analyst selected a random sample of 800 cars traveling on I-195 in Miami on a weekday morning. Among the 800 cars in the sample, 24% were white. The margin of error for this estimate is 3.0 percentage points.a. Would you be surprised if a census revealed that 26% of cars
A Gallup poll conducted telephone interviews with a random sample of 1000 adults aged 18 and older. Of these, 37% said that football is their favorite sport to watch on television. The margin of error for this estimate is 3.1 percentage points.a. Would you be surprised if a census revealed that 50%
What proportion of students at your school use Twitter? To find out, you survey a simple random sample of students from the school roster.a. Will your sample result be exactly the same as the true population proportion? Explain your answer.b. Which would be more likely to produce a sample result
The boxplots summarize the distributions of average monthly rainfall (in inches) for Tucson, Arizona, and Princeton, New Jersey.52 Compare these distributions. Princeton - Tucson -E 1 2 3 4 5 Average monthly rainfall (in.) Location
A researcher wants to estimate the average distance that students at a large community college live from campus. To find out, she surveys a simple random sample of students from the registrar’s database.a. Will the researcher’s sample result be exactly the same as the true population mean?
Biological measurements on the same species often follow a Normal distribution quite closely. The weights of seeds of a variety of winged bean are approximately Normal with mean 525 milligrams (mg) and standard deviation 110 mg.a. What percent of seeds weigh more than 500 mg?b. If we discard the
Two essential features of all statistically designed experiments area. Comparing several treatments; using the double-blind method.b. Comparing several treatments; using chance to assign subjects to treatments.c. Always having a placebo group; using the double-blind method.d. Using a block design;
A report in a medical journal notes that the risk of developing Alzheimer’s disease among subjects who regularly opted to take the drug ibuprofen was about half the risk of those who did not. Is this good evidence that ibuprofen is effective in preventing Alzheimer’s disease?a. Yes, because the
A farmer is conducting an experiment to determine which variety of apple tree, Fuji or Gala, will produce more fruit in his orchard. The orchard is divided into 20 equally sized square plots. He has 10 trees of each variety and randomly assigns each tree to a separate plot in the orchard. What are
Corn variety 1 yielded 140 bushels per acre last year at a research farm. This year, corn variety 2, planted in the same location, yielded only 110 bushels per acre. Based on these results, is it reasonable to conclude that corn variety 1 is more productive than corn variety 2? a. Yes,
A gardener wants to try different combinations of fertilizer (none, 1 cup, 2 cups) and mulch (none, wood chips, pine needles, plastic) to determine which combination produces the highest yield for a variety of green beans. He has 60 green-bean plants to use in the experiment. If he wants an equal
To investigate if standing up while studying affects performance in an algebra class, a teacher assigns half of the 30 students in his class to stand up while studying and assigns the other half to not stand up while studying. To determine who receives which treatment, the teacher identifies the
In the experiment of the preceding exercise, the subjects were randomly assigned to the different treatments. What is the most important reason for this random assignment?a. Random assignment eliminates the effects of other variables such as stress and body weight.b. Random assignment is a good way
Can a vegetarian or low-salt diet reduce blood pressure? Men with high blood pressure are assigned at random to one of four diets:(1) Normal diet with unrestricted salt;(2) Vegetarian with unrestricted salt;(3) Normal with restricted salt; (4) Vegetarian with restricted salt. This experiment
Which of two brands (X or Y) of electric razor shaves closer? Researchers want to design and carry out an experiment to answer this question using 50 adult male volunteers. Here’s one idea: Have all 50 subjects shave the left sides of their faces with the Brand X razor and shave the right sides
A group of students wants to perform an experiment to determine whether Brand A or Brand B deodorant lasts longer. One group member suggests the following design: Recruit 40 student volunteers 20 male and 20 female. Separate by gender, because male and female bodies might respond differently to
Does talking on a hands-free cell phone distract drivers? Researchers recruit 40 student subjects for an experiment to investigate this question. They have a driving simulator equipped with a hands-free phone for use in the study. Each subject will complete two sessions in the simulator: one while
Cardiologists at Athens Medical School in Greece wanted to test if chocolate affects blood vessel function. The researchers recruited 17 healthy young volunteers, who were each given a 3.5-ounce bar of dark chocolate, either bittersweet or fake chocolate. On another day, the volunteers received the
Medical researchers want to compare the success rate of a new non invasive method for replacing heart valves using a cardiac catheter with traditional open-heart surgery. They have 40 male patients, ranging in age from 55 to 75, who need valve replacement. One of several response variables will be
A total of 20 overweight females have agreed to participate in a study of the effectiveness of four weight-loss treatments: A, B, C, and D. The researcher first calculates how overweight each subject is by comparing the subject’s actual weight with her “ideal” weight. The subjects and their
A school counselor wants to compare the effectiveness of an online SAT preparation program with an in-person SAT preparation class. For an experiment, the counselor recruits 30 students who have already taken the SAT once. The response variable will be the improvement in SAT score.a. Design an
A nutrition experimenter intends to compare the weight gain of newly weaned male rats fed Diet A with that of rats fed Diet B. To do this, she will feed each diet to 10 rats. She has available 10 rats from one litter and 10 rats from a second litter. Rats in the first litter appear to be slightly
Nurse-practitioners are nurses with advanced qualifications who often act much like primary-care physicians. Are they as effective as doctors at treating patients with chronic conditions? An experiment was conducted with 1316 patients who had been diagnosed with asthma, diabetes, or high blood
The progress of a type of cancer differs in women and men. Researchers want to design an experiment to compare three therapies for this cancer. They recruit 500 male and 300 female patients who are willing to serve as subjects.a. Which are the blocks in this experiment: the three cancer therapies
An agriculture researcher wants to compare the yield of 5 corn varieties: A, B, C, D, and E. The field in which the experiment will be carried out increases in fertility from north to south. The researcher therefore divides the field into 25 plots of equal size, arranged in 5 east–west rows of 5
A citrus farmer wants to know which of three fertilizers (A, B, and C) is most effective for increasing the number of oranges on his trees. He is willing to use 30 mature trees of various sizes from his orchard in an experiment with a randomized block design.a. Describe a randomized block design
A large study of 3000 Canadian children and their mothers found that the children of mothers who drank diet soda daily during pregnancy were twice as likely to be overweight at age 1 than children of mothers who avoided diet soda during pregnancy.a. A newspaper article about this study had the
A large study used records from Canada’s national health care system to compare the effectiveness of two ways to treat prostate disease. The two treatments are traditional surgery and a new method that does not require surgery. The records described many patients whose doctors had chosen what
Does day care help low-income children stay in school and hold good jobs later in life? The Carolina Abecedarian Project (the name suggests the ABCs) has followed a group of 111 children for over 40 years. Back then, these individuals were all healthy but low-income black infants in Chapel Hill,
Do blood-building drugs help brain development in babies born prematurely? Researchers randomly assigned 53 babies, born more than a month premature and weighing less than 3 pounds, to one of three groups. Babies either received injections of erythropoietin (EPO) three times a week, darbepoetin
A biologist would like to determine which of two brands of weed killer, X or Y, is less likely to harm the plants in a garden at the university. Before spraying near the plants, the biologist decides to conduct an experiment using 24 individual plants. Which of the following two plans for randomly
A football coach hears that a new exercise program will increase upper body strength better than lifting weights. He is eager to test this new program in the off-season with the players on his high school team. The coach decides to let his players choose which of the two treatments they will
People often use round prices as first offers in a negotiation. But would a more precise number suggest that the offer was more reasoned and informed? In an experiment, 238 adults played the role of a person selling a used car. Each adult received one of three initial offers: $2000, $1865 (a
Workers who survive a layoff of other employees at their location may suffer from “survivor guilt.” A study of survivor guilt and its effects used as subjects 120 students who were offered an opportunity to earn extra course credit by doing proofreading. Each subject worked in the same cubicle
Even if an experiment is double-blind, the blinding might be compromised if side effects of the treatments differ. For example, suppose researchers at a skin-care company are comparing their new acne treatment against that of the leading competitor. Fifty subjects are assigned at random to each
An experiment that claimed to show that meditation lowers anxiety proceeded as follows. The experimenter interviewed the subjects and rated their level of anxiety. Then the subjects were randomly assigned to two groups. The experimenter taught one group how to meditate and they meditated daily for
Refer to Exercise 56. Could blinding be used in this experiment? Explain your reasoning. Why is blinding an important consideration in this context?Exercise 56.As men age, their testosterone levels gradually decrease. This may cause a reduction in energy, an increase in fat, and other undesirable
Refer to Exercise 55. Could blinding be used in this experiment? Explain your reasoning. Why is blinding an important consideration in this context?Exercise 55.The extracts of avocado and soybean oils have been shown to slow cell inflammation in test tubes. Will taking avocado and soybean
Will cash bonuses speed the return to work of unemployed people? A state department of labor notes that last year 68% of people who filed claims for unemployment insurance found a new job within 15 weeks. As an experiment, this year the state offers $500 to people filing unemployment claims if they
A study of blood flow involved 27 healthy people aged 18 to 72. Each subject consumed a cocoa beverage containing 900 milligrams of flavonols daily for 5 days. Using a finger cuff, blood flow was measured on the first and fifth days of the study. After 5 days, researchers measured what they called
As men age, their testosterone levels gradually decrease. This may cause a reduction in energy, an increase in fat, and other undesirable changes. Do testosterone supplements reverse some of these effects? A study in the Netherlands assigned 237 men aged 60 to 80 with low or lownormal testosterone
The extracts of avocado and soybean oils have been shown to slow cell inflammation in test tubes. Will taking avocado and soybean unsaponifiables (called ASU) help relieve pain for subjects with joint stiffness due to arthritis? In an experiment, 345 men and women were randomly assigned to receive
The cost of a meal might affect how customers evaluate and appreciate food. To investigate, researchers worked with an Italian all-you-can-eat buffet to perform an experiment. A total of 139 subjects were randomly assigned to pay either $4 or $8 for the buffet and then asked to rate the quality of
Can snacking on fruit rather than candy reduce later food consumption? Researchers randomly assigned 12 women to eat either 65 calories of berries or 65 calories of candy. Two hours later, all 12 women were given an unlimited amount of pasta to eat. The researchers recorded the amount of pasta
A maker of fabric for clothing is setting up a new line to “finish” the raw fabric. The line will use either metal rollers or natural-bristle rollers to raise the surface of the fabric; a dyeingcycle time of either 30 or 40 minutes; and a temperature of either 150°C or 175°C. Three specimens
How can we reduce the rate of refusals in telephone surveys? Most people who answer at all listen to the interviewer’s introductory remarks and then decide whether to continue. One study made telephone calls to randomly selected households to ask opinions about the next election. In some calls,
Many children have their molars sealed to help prevent cavities. In an experiment, 120 children aged 6–8 were randomly assigned to a control group, a group in which sealant was applied and reapplied periodically for 36 months, and a group in which fluoride varnish was applied and reapplied
A University of Helsinki (Finland) study wanted to determine if chocolate consumption during pregnancy had an effect on infant temperament at age 6 months. Researchers began by asking 305 healthy pregnant women to report their chocolate consumption. Six months after birth, the researchers asked

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The Practice Of Statistics 6th Edition Daren S. Starnes, Josh Tabor - Solutions

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