A stock analyst wants to know if there is a difference between the mean rate of return from energy stocks and that from financial stocks. He randomly selects 13 energy stocks and computes the rate of return for the past year. He randomly selects 13 financial stocks and computes the rate of return for the past year.
> A random sample of 2163 adults (aged 18 and over) was asked, “Given a choice of the following, which one would you most want to be?” The results of the survey are presented in the side-by-side bar graph. (a) What proportion of males would like to be rich
> A random sample of 2163 adults (aged 18 and over) was asked, “When you see an ad emphasizing that a product is ‘Made in America,’ are you more likely to buy it, less likely to buy it, or neither more nor less likely to buy it?” The results of the survey
> Identity fraud occurs when someone else’s personal information is used to open credit card accounts, apply for a job, receive benefits, and so on. The following relative frequency bar graph represents the various types of identity theft based on a study
> The following graph represents the results of a survey, in which a random sample of adult Americans was asked, “Please tell me whether you personally believe that in general divorce is morally acceptable or morally wrong.” (a) What percent of the respond
> The U.S. Census Bureau uses money income thresholds to define poverty. For example, in 2018 the poverty threshold for a family of four with two children was $25,100. The bar graph represents the number of people living in poverty (in thousands) in the Un
> The following Pareto chart shows the position played by the most valuable player (MVP) in the National League since 1931. Source:http://www.baseball-almanac.com/ (a) Which position had the most MVPs? (b) How many MVPs played first base (1B)? (c) How many
> Season The pie chart shown, the type we see in USA Today, depicts the approaches people use to avoid getting the flu. (a) What is the most common approach? What percentage of the population chooses this method? (b) What is the least used approach? What p
> This USA Today–type chart shows the top responses to the question, “Who’s the most difficult to ‘sell yourself’ to?” (a) What was the most common response? (b) The survey is of 1053 adults. How many stated their significant other is most difficult to “se
> Internet connection speed in kilobytes per second
> What is a bar graph? What is a Pareto chart?
> Observational studies are used to determine causality between an explanatory variable and response variable.
> A(n)_____design is one in which each experimental unit is randomly assigned to a treatment. A(n)____design is one in which the experimental units are paired up.
> Explain the difference between a single-blind and a double- blind experiment.
> What is replication in an experiment?
> Define the following: (a) Experimental unit (b) Treatment (c) Response variable (d) Factor (e) Placebo (f) Confounding (g) Blinding
> Treatments may be a combination of factors rather than a single factor. For example, suppose we want to investigate the role of diet and drugs in weight loss. Suppose we have three diet plans (a saturated-fat diet, the Mediterranean diet, or the U.S. Nat
> What is the role of randomization in a designed experiment? If you were conducting a completely randomized design with three treatments and 90 experimental units, describe how you would randomly assign the experimental units to the treatments.
> Research the link between the release of dopamine and the placebo effect.
> In May, 2020, the biotechnology company Novavax began human trials of its Covid-19 vaccine. The Phase I trial was a placebo-controlled, observer-blinded design. Most clinical trials go through five phases: Phase 0 (Pre-clinical), Phase I (Safety), Phase
> Number of Sequoia trees in a randomly selected acre of Yosemite National Park
> Match each word or phrase with its definition.
> Match each word or phrase with its definition.
> Time to complete the 500-meter race in speed skating.
> What is meant by the process of statistics?
> In October 2014, there was an Ebola breakout in West Africa. At the time, there was no vaccine for the virus, however, there were some experimental drugs that had not yet been approved for humans. Because the spread of the disease was reaching an epidemi
> List the four components that comprise the definition of statistics.
> A researcher believes that as age increases, the grip strength (pounds per square inch, psi) of an individual’s dominant hand decreases. From a random sample of 17 females, he obtains the following data. (a) Treating age as the explanatory variable, dete
> The following data represent the height (inches) of boys between the ages of 2 and 10 years. (a) Treating age as the explanatory variable, determine the estimates of /. What is the mean height of a 7-year-old boy? (b) Compute the standard error of the es
> Crickets make a chirping noise by sliding their wings rapidly over each other. Perhaps you have noticed that the number of chirps seems to increase with the temperature. The following table lists the temperature (in degrees Fahrenheit, °F) and the number
> State the requirements to perform inference on a simple least-squares regression line.
> Many municipalities are passing legislation that forbids smoking in restaurants and bars. Bar owners claim that these laws hurt their business. Are their concerns legitimate? The following data represent the smoking status and frequency of visits to bars
> The General Social Survey regularly asks individuals to disclose their religious affiliation. The following data represent the religious affiliation of young adults, aged 18 to 29, in the 1970s, 1980s, 1990s, and 2000s. Do the data suggest different prop
> The Harris Poll asked a random sample of adult Americans, “How important are moral values when deciding how to vote?” The results of the survey by disclosed political affiliation are shown in the table. (a) Do the sample data suggest that the proportion
> A researcher wanted to determine if the distribution of educational attainment of Americans today is different from the distribution in 2000. The distribution of educational attainment in 2000 was as follows: The researcher randomly selects 500 Americans
> A pit boss is concerned that a pair of dice being used in a craps game is not fair. The distribution of the expected sum of two fair dice is as follows: The pit boss rolls the dice 400 times and records the sum of the dice. The table shows the results. D
> In their book SuperFreakonomics, authors Steven Levitt and Stephen Dubner describe the research of behavioral economist John List. List recruited customers and dealers at a baseball-card show to participate in an experiment in which the customer would st
> Researchers had a car traveling 10 miles per hour collide into the rear bumper of an SUV and recorded the amount of damage, in dollars. The data are below. Do the given data suggest the repair cost of the car is higher? Use the = 0.1 level of significa
> In a study conducted to determine the role that sleep disorders play in academic performance, researcher Jane Gaultney conducted a survey of 1845 college students to determine if they had a sleep disorder (such as narcolepsy, insomnia, or restless leg sy
> A researcher wants to know whether the acidity of rain (pH) near Houston, Texas, is significantly different from that near Chicago, Illinois. He randomly selects 12 rain dates in Texas and 14 rain dates in Illinois and obtains the following data: (a) Is
> A random sample of n1 = 650 individuals results in x1 = 156 successes. An independent sample of n2 = 550 individuals results in x2 = 143 successes. Does this represent sufficient evidence to conclude that / at the = 0.05 level of significance?
> Test the hypothesis that /level of significance for the given sample data.
> (a) Test the hypothesis that / level of significance for the given sample data. (b) Construct a 95% confidence interval for /
> (a) Compute /for each pair of data. (b) Compute /. (c) Test the hypothesis that /level of significance. (d) Compute a 95% confidence interval for the population mean difference /
> A prison warden wants to know if men receive longer sentences for crimes than women. He randomly samples 30 men and matches them with 30 women by type of crime committed and records their lengths of sentence.
> It is commonplace to gain weight after quitting smoking. To determine the effectiveness of the drug Naltrexone in limiting weight gain after quitting smoking, 147 subjects who smoked 20 or more cigarettes daily were randomly divided into two groups. All
> A researcher wants to estimate the difference between the percentage of individuals without a high school diploma who smoke and the percentage of individuals with bachelor’s degrees who smoke. What sample size should be obtained if she wishes the estimat
> Design an experiment where the goal is to determine whether people prefer Coke or Pepsi. In the design, be sure to identify the response variable, the role of blinding, and randomization.
> Does hypnotism result in a different success rate for men and women who are trying to quit smoking? Researchers at Science magazine analyzed studies involving 5600 male and female smokers. Of the 2800 females, 644 quit smoking; of the 2800 males, 840 qui
> Zoloft is a drug used to treat obsessive-compulsive disorder (OCD). In randomized, double-blind clinical trials, 926 patients diagnosed with OCD were randomly divided into two groups. Subjects in group 1 (experimental group) received 200 milligrams per d
> According to the Pew Research Center, the proportion of the American population who use only a cellular telephone (no landline) is 0.37. Jason conducts a survey of thirty 20- to 24-year-olds who live on their own and finds that 16 do not have a landline
> A Zone diet is one with a 40%–30%–30% distribution of carbohydrate, protein, and fat, respectively, and is based on the book Enter the Zone. In a study conducted by researchers Christopher Gardner and associates, 79 subjects were administered the Zone di
> In many parliamentary procedures, a supermajority is defined as an excess of 60% of voting members. In a poll conducted by the Gallup organization on May 10, 1939, 1561 adult Americans were asked, “Do you think the United States will have to fight Japan
> The outside diameter of a manufactured part must be 1.3825 inches, according to customer specifications. The data shown represent a random sample of ten parts. Use a 95% confidence interval to judge whether the part has been manufactured to specification
> “Did you get your 8 hours of sleep last night?” is a common question. In a recent survey of 151 postpartum women, the folks at the National Sleep Foundation found that the mean sleep time was 7.8 hours, with a standard deviation of 1.4 hours. Does the ev
> The trade magazine QSR routinely examines fast-food drive-thru service times. Their recent research indicates that the mean time a car spends in a McDonald’s drive- thru is 167.1 seconds. A McDonald’s manager in Salt Lake City feels that she has insti
> According to the American Time Use Survey, adult Americans spent 42.6 minutes per day on phone calls and answering or writing email in 2006. (a) Suppose that we want to judge whether the amount of daily time spent on phone calls and answering or writing
> Research the placebo effect and the Hawthorne effect. Write a paragraph that describes how each affects the outcome of an experiment.
> A tennis enthusiast wants to estimate the mean length of men’s singles matches held during the Wimbledon tennis tournament. From the Wimbledon history archives, he randomly selects 40 matches played during the tournament since the year 1968 (when profess
> From a random sample of 1201 Americans, it was discovered that 1139 of them lived in neighborhoods with acceptable levels of carbon monoxide. Source: Environmental Protection Agency. (a) Obtain a point estimate for the proportion of Americans who live in
> The campus at Joliet Junior College has a lake. A student used a Secchi disk to measure the clarity of the lake’s water by lowering the disk into the water and measuring the distance below the water surface at which the disk is no longer visible. The fol
> A random sample of 50 recent college graduates results in a mean time to graduate of 4.58 years, with a standard deviation of 1.10 years. Source: Based on data from The Toolbox Revisited by Clifford Adelman, U.S. Department of Education. (a) Compute and
> A question on the General Social Survey was this: “How many family members do you know that are in prison?” The results of 499 respondents indicate that the mean number of family members in jail is 1.22, with a standard deviation of 0.59. (a) What shape
> Determine the point estimate of the population mean and margin of error if the confidence interval has lower bound: 125.8 and upper bound: 152.6.
> Find the critical t-value for constructing a confidence interval about a population mean at the given level of confidence for the given sample size, n. (a) 96% confidence; n = 26 (b) 98% confidence; n = 18
> Net worth is defined as total assets (value of house, cars, money, etc.) minus total liabilities (mortgage balance, credit card debt, etc.). According to a recent study by TNS Financial Services, 7% of American households had a net worth in excess of $1
> Distinguish between sampling and nonsampling error.
> Peanut and tree nut allergies are considered to be the most serious food allergies. According to the National Institute of Allergy and Infectious Diseases, roughly 1% of Americans are allergic to peanuts or tree nuts. A random sample of 1500 Americans is
> Search a newspaper, magazine, or other periodical that describes an experiment. Identify the population, experimental unit, response variable, treatment, factors, and their levels.
> List and explain the three sources of bias in sampling. Provide some methods that might be used to minimize bias in sampling.
> According to the National Center for Health Statistics, 22.4% of adults are smokers. A random sample of 300 adults is obtained. (a) Describe the sampling distribution of /, the sample proportion of adults who smoke. (b) In a random sample of 300 adults,
> What is meant by the process of statistics?
> A machine used for filling plastic bottles with a soft drink has a known standard deviation of = 0.05 liter. The target mean fill volume is = 2.0 liters. (a) Describe the sampling distribution of /, the sample mean fill volume, for a random sample of
> List and describe the three major types of observational studies.
> The charge life of a certain lithium ion battery for camcorders is normally distributed, with mean 90 minutes and standard deviation 35 minutes. (a) What is the probability that a randomly selected battery of this type lasts more than 100 minutes on a si
> Define each of the following. (a) Response variable (b) Variable (c) Qualitative variable (d) Quantitative variable (e) Observational study (f) Designed experiment (g) Confounding (h) Lurking variable
> If a random sample of size 36 is obtained from a population with mean 50 and standard deviation 24, what is the mean and standard deviation of the sampling distribution of the sample mean?
> The following data represent the square footage and rents for apartments in Queens, New York and Nassau County, New York. For this problem, only consider the Queens data. (a) What are the estimates of /? What is the mean rent of a 900-square-foot apartme
> State the Central Limit Theorem.
> Researchers want to know if there is a link between hypertension (high blood pressure) and consumption of salt. Past studies have indicated that the consumption of fruits and vegetables offsets the negative impact of salt consumption. It is also known th
> A biology professor wants to investigate the relation between the seat location chosen by a student on the first day of class and their cumulative grade point average (GPA). He randomly selected an introductory biology class and obtained the following in
> In a poll conducted by the Gallup organization, 16% of adult, employed Americans were dissatisfied with the amount of their vacation time. You conduct a survey of 500 adult, employed Americans. (a) Approximate the probability that exactly 100 are dissati
> What is the simple least-squares regression model? What are the requirements to perform inference on a simple least-squares regression line? How do we verify that these requirements are met?
> Suppose the scores earned on Professor McArthur’s third statistics exam are normally distributed with mean 64 and standard deviation 8. Professor McArthur wants to curve the exam scores as follows: The top 6% get an A, the next 14% get a B, the middle 60
> In the General Social Survey, individuals were asked whether civic duty included voting and whether it included serving on a jury. The results of the survey are shown in the table. Is there a difference in the proportion of individuals who feel jury duty
> The waist circumference of males 20–29 years old is approximately normally distributed, with mean 92.5 cm and standard deviation 13.7 cm. Source: M. A. McDowell, C. D. Fryar, R. Hirsch, and C. L. Ogden. Anthropometric Reference Data for Children and Adul
> One of the most famous presidential elections (from a statistician’s point of view) is the 1936 contest between incumbent Franklin D. Roosevelt (FDR) and Republican challenger Alf Landon. The notoriety of the election comes from the fact that polling don
> Suppose that the talk time on the Apple iPhone is approximately normally distributed with mean 7 hours and standard deviation 0.8 hour. (a) What proportion of the time will a fully charged iPhone last at least 6 hours? (b) What is the probability a fully
> Does the length of term of pregnancy play a role in the level of education of the baby? Researchers in Norway followed over 1 million births between 1967 and 1988 and looked at the educational attainment of the children. The following data are based on t
> (a) Draw a normal curve with = 20 and = 3. (b) Shade the region that represents / and find the probability.
> An engineer has just developed a new tire design. However, before going into production, the tire company wants to determine if the new tire reduces braking distance on a car traveling 60 miles per hour compared with radial tires. Design an experiment to
> With 20% of men, 74% of women, and 52% of children surviving the infamous Titanic disaster, it is clear that the saying “women and children first” was followed. But what, if any, role did the class of service play in the survival of passengers? The data
> Find the value of z0.04.
> Are the teams that play in the World Series evenly matched? To win a World Series, a team must win four games. If the teams are evenly matched, we would expect the number of games played in the World Series to follow the distribution shown in the first t
> Find the z-scores that separate the middle 88% of the data from the area in the tails of the standard normal distribution.
> The following data represent the number of calories per serving and the number of grams of sugar per serving for a random sample of high-protein and moderate-protein energy bars. (a) Draw a scatter diagram of the data, treating calories as the explanator
> Draw a standard normal curve and shade the area to the right of z = 2.04. Then find the area of the shaded region.
> A pit boss suspects that a roulette wheel is out of balance. A roulette wheel has 18 black slots, 18 red slots, and 2 green slots. The pit boss spins the wheel 500 times and records the following frequencies: Is the wheel out of balance? Use the = 0.05
> A continuous random variable X is uniformly distributed with / (a) Draw a graph of the uniform density function. (b) What is / (c) What is /
> Osteoporosis is a condition in which people experience decreased bone mass and an increase in the risk of bone fracture. Actonel is a drug that helps combat osteoporosis in postmenopausal women. In clinical trials, 1374 postmenopausal women were rando
> A student wanted to determine whether the wait time in the drive-thru at McDonald’s differed from that at Wendy’s. She used a random sample of 30 cars at McDonald’s and 27 cars at Wendy’s and obtained these results: Note: The sample size for Wendy’s is l
