A survey was conducted at a community college of 50 randomly selected students who dropped a course in the current semester to learn why students drop courses. “Personal” drop reasons include financial, transportation, family issues, health issues, and lack of child care. “Course” drop reasons include reducing one’s load, being unprepared for the course, the course was not what was expected, dissatisfaction with teaching, and not getting the desired grade. “Work” drop reasons include an increase in hours, a change in shift, and obtaining fulltime employment. Go to www.pearsonhighered.com/sullivanstats to obtain the data file 12_2_17 using the file format of your choice for the version of the text you are using. (a) Construct a contingency table for the two variables. (b) Test whether gender is independent of drop reason at the = 0.1 level of significance. (c) Construct a conditional distribution of drop reason by gender and draw a bar graph. Does this evidence support your conclusion in part (b)?
> Use the results of Problem 15 from Section 12.3 to answer the following questions: (a) Predict the mean 28-day strength of concrete whose 7-day strength is 2550 psi. (b) Construct a 95% confidence interval for the mean 28-day strength of concrete whose 7
> Use the results of Problem 14 in Section 12.3 to answer the following questions: (a) Predict the mean wind speed of all hurricanes whose atmospheric pressure is 950 mb. (b) Construct a 95% confidence interval for the mean wind speed found in part (a). (c
> Use the results of Problem 13 from Section 12.3 to answer the following questions: (a) Predict the mean head circumference of children who are 25.75 inches tall. (b) Construct a 95% confidence interval for the mean head circumference of children who are
> Use the results of Problem 12 from Section 12.3 to answer the following questions: (a) Predict the mean interest rate of all individuals whose credit score is 730. (b) Construct a 90% confidence interval for the mean interest rate of all individuals whos
> If /is not rejected, what is the best estimate for the value of the response variable for any value of the explanatory variable?
> In the least-squares regression model, / / is a random error term with mean_____ and standard deviation /
> What are some solutions to nonresponse?
> True or False: In a least-squares regression, the response variable is normally distributed with mean / and standard deviation .
> Suppose a least-squares regression line is given by / = 4.302x - 3.293. What is the mean value of the response variable if x = 20?
> Why don’t we conduct inference on the linear correlation coefficient?
> Why is it desirable to have the explanatory variables spread out to test a hypothesis regarding 1 or to construct confidence intervals about 1?
> What do the y-coordinates on the least-squares regression line represent?
> Why is it important to perform graphical as well as analytical analyses when analyzing relations between two quantitative variables?
> Zillow.com is a site that can be used to assess the value of homes in your neighborhood. The organization provides a list of homes for sale as well as a Zestimate, which is the price Zillow believes the home will sell for. The following data represent th
> The output shown was obtained from Minitab. (a) The least-squares regression equation is / = 1.3962x + 12.396. What is the predicted value of y at x = 10? (b) What is the mean of y at x = 10? (c) The standard error, se, is 2.167. What is an estimate of
> A doctor wanted to determine whether there is a relation between a male’s age and his HDL (so-called good) cholesterol. He randomly selected 17 of his patients and determined their HDL levels. He obtained the following data. (a) Draw a scatter diagram of
> A bear market is a market condition in which the price of the security falls. A bear market in the stock market is defined as a condition in which the market declines by 20% or more over the course of at least two months. The following data represent the
> Why is it rare for frames to be completely accurate?
> The following data represent the total compensation for 12 randomly selected chief executive officers (CEOs) and the company’s stock performance in 2017. (a) Treating compensation as the explanatory variable, x, determine the estimates of / (b) Assuming
> In 1969, Dr. Michael R. Pelton of the University of Tennessee initiated a long-term study of the American black bear (Ursus americanus) population in Great Smoky Mountains National Park. One aspect of the study was to develop a model that could be used t
> Go to www.pearsonhighered.com/ sullivanstats to obtain the data file 12_3_17. The variable “Cost” represents the four-year cost including tuition, supplies, room and board, the variable “Annual ROI” represents the return on investment for graduates of th
> Every year the Federal Trade Commission (FTC) must report tar and nicotine levels in cigarettes to Congress. Tar and nicotine levels of over 1200 brands of cigarettes are given to Congress and a random sample of those appear in the following table: (a) T
> As concrete cures, it gains strength. The following data represent the 7-day and 28-day strength (in pounds per square inch) of a certain type of concrete: (a) Treating the 7-day strength as the explanatory variable, x, determine the estimates of / (b) C
> The following data represent the maximum wind speed (in knots) and atmospheric pressure (in millibars) for a random sample of hurricanes that originated in the Atlantic Ocean. Does atmospheric pressure play a role in the wind speed of a hurricane? Use th
> A pediatrician wants to determine the relation that may exist between a child’s height and head circumference. She randomly selects 11 children from her practice, measures their heights and head circumferences, and obtains the following data: Use the res
> An economist wants to determine the relation between one’s FICO score, x, and the interest rate of a 36-month auto loan, y. The data represent the interest rate (in percent) a bank might offer on a 36-month auto loan for various FICO scores. Use the resu
> The following data represent commute times (in minutes) and a score on a well-being survey. Use the results from Problem 17 in Section 4.2 to answer the following questions: (a) Treating commute time as the explanatory variable, x, determine the estimate
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> One of the challenges in polling for elections is deciding who to include in your frame and who might actually turn out to vote. (a) Suppose you were asked to conduct a poll for a senatorial election. Explain how you might design your sample. In your exp
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> The following table contains observed values and expected values in parentheses for two categorical variables, X and Y, where variable X has three categories and variable Y has two categories. (a) Compute the value of the chi-square test statistic. (b) T
> The following table contains observed values and expected values in parentheses for two categorical variables, X and Y, where variable X has three categories and variable Y has two categories (a) Compute the value of the chi-square test statistic. (b) Te
> In a chi-square test for_______ of proportions, we test whether different populations have the same proportion of individuals with some characteristic.
> True or False: The expected frequencies in a chi-square test for independence are found using the formula
> Why does the test for homogeneity follow the same procedures as the test for independence?
> Research the polling done by George Gallup in the 1936 presidential election. Write a report on your findings and include information about the sampling technique and sample size. Next, research the polling done by Gallup for the 1948 presidential electi
> Goals scored in a season by a soccer player
> Explain the differences between the chi-square test for independence and the chi-square test for homogeneity. What are the similarities?
> Go to www.pearsonhighered.com/sullivanstats to obtain the data file 12_2_24 using the file format of your choice for the version of the text you are using. The variable “TrueDist” represents the distance, in feet, that the homerun traveled for all homeru
> During the fall semester of 2014, the University of North Georgia developed a corequisite College Algebra course. In this approach, students who would otherwise place in a Learning Support (LS) course in one semester and then enroll in College Algebra th
> In a famous study by the Physicians Health Study Group from Harvard University from the late 1980s, 22,000 healthy male physicians were randomly divided into two groups; half the physicians took aspirin every other day, and the others were given a placeb
> Researchers at the City University of New York (CUNY) identified 717 students who originally placed into an Elementary Algebra course. The students agreed to participate in a study related to the roll of corequisite remediation and study skills. In this
> A study by InsuranceQuotes.com found that homeowners with poor credit pay 91% more for home insurance than people with excellent credit. (a) A quote in the article stated, “Insurers have found a direct correlation between a consumer’s credit and the like
> Traditional underwriting to determine the risks associated with lending include credit scores, income, and employment history. The online lender ZestFinance used data analysis to find that people who fill out loan applications using all capital letters d
> In the Sullivan Statistics Survey, respondents were asked to disclose their political affiliation (Democrat, Independent, Republican) and also answer the question: “Would you be willing to pay higher taxes if the tax revenue went directly toward deficit
> In a recent survey conducted by the Pew Research Center, a random sample of adults 18 years of age or older living in the continental United States was asked their reaction to the word capitalism. In addition, the individuals were asked to disclose which
> Name two biases that led to the Literary Digest making an incorrect prediction in the presidential election of 1936.
> In a recent survey conducted by the Pew Research Center, a random sample of adults 18 years of age or older living in the continental United States was asked their reaction to the word socialism. In addition, the individuals were asked to disclose which
> Celebrex, a drug manufactured by Pfizer, Inc., is used to relieve symptoms associated with osteoarthritis and rheumatoid arthritis in adults. In clinical trials of the medication, some subjects reported dizziness as a side effect. The researchers wanted
> Do electronic cigarettes assist in helping individuals quit smoking? Researchers found 300 current smokers to volunteer for a study in which each was randomly assigned to one of three treatment groups. Group 1 received an electronic cigarette (e-cig) in
> The following data represent the smoking status from a random sample of 1054 U.S. residents 18 years or older by level of education. (a) Test whether smoking status and level of education are independent at the = 0.05 level of significance. (b) Constru
> The Gallup Organization conducted a survey asking individuals questions pertaining to social well-being such as strength of relationship with spouse, partner, or closest friend, making time for trips or vacations, and having someone who encourages them t
> Does amount of education play a role in the healthiness of an individual? The following data represent the level of health and the highest degree earned for a random sample of individuals from the General Social Survey. (a) Does the evidence suggest that
> Are health and happiness related? The following data represent the level of happiness and level of health for a random sample of individuals from the General Social Survey. (a) Does the evidence suggest that health and happiness are related? Use the =
> An obstetrician wants to learn whether the amount of prenatal care and the wantedness of the pregnancy are associated. He randomly selects 939 women who had recently given birth and asks them to disclose whether their pregnancy was intended, unintended,
> A sociologist wants to discover whether the sexual activity of females between the ages of 15 and 19 years and family structure are associated. She randomly selects 380 females between the ages of 15 and 19 years and asks each to disclose her family stru
> The following table contains the number of successes and failures for three categories of a variable. Test whether the proportions are equal for each category at the = 0.01 level of significance.
> People often respond to survey questions without any knowledge of the subject matter. A common example of this is the discussion on banning dihydrogen monoxide. The Centers for Disease Control (CDC) reports that there were 1423 deaths due to asbestos in
> The following table contains the number of successes and failures for three categories of a variable. Test whether the proportions are equal for each category at the = 0.01 level of significance.
> A_______ test is an inferential procedure used to determine whether a frequency distribution follows a specific distribution.
> True or False: The shape of the chi-square distribution depends on the degrees of freedom.
> A “nine-ender” is an individual whose age ends in 9 (as in 29, 39, 49 years of age). Some studies have suggested that nine-enders tend to participate in certain activities at a higher rate than those whose age ends in the digits 0 through 8. For example,
> If the expected count of a category is less than 1, what can be done to the categories so that a goodness-of-fit test can still be performed?
> Explain why chi-square goodness-of-fit tests are always right tailed.
> Why is goodness of fit a good choice for the title of the procedures used in this section?
> How much does the typical person pay for a new 2019 Audi A4? The following data represent the selling price of a random sample of new A4s (in dollars). (a) Is this data quantitative or qualitative? (b) Find the mean and median price of a new 2019 A4. (c)
> On February 2, 1894, Frank Raphael Weldon wrote a letter to Francis Galton that included the results of 26,306 rolls of 12 dice. Weldon recorded the results such that a roll of a 5 or 6 resulted in a success, while a roll of 1, 2, 3, or 4 was a failure.
> In Thomas Pynchon’s book Gravity Rainbow, the characters discuss whether the Poisson probabilistic model can be used to describe the locations that Germany’s feared V-2 rocket would land in. They divided London into 0.25-km2 regions. They then counted th
> Write two questions that could have different responses, depending on the order in which the questions are presented. Or write a single question such that the order in which words are presented could affect the response. Administer the survey to at least
> In 2000, 25.8% of Americans 15 years of age or older lived alone, according to the Census Bureau. A sociologist, who believes that this percentage is greater today, conducts a random sample of 400 Americans 15 years of age or older and finds that 164 are
> According to the U.S. Census Bureau, 7.1% of all babies born are of low birth weight 1 65 lb, 8 oz2. An obstetrician wanted to know whether mothers between the ages of 35 and 39 years give birth to a higher percentage of low-birth-weight babies. She rand
> An urban economist wonders if the distribution of U.S. residents in the United States is different today than it was in 2000. The table shows the distribution of residents in 2000 along with the observed counts of residents today based on a random sample
> At Joliet Junior College, the mathematics department decided to offer a redesigned course in Intermediate Algebra, called the Math Redesign Program (MRP). Laura Egner, the coordinator of the program, wanted to determine if the grade distribution in the c
> A researcher wanted to determine whether pedestrian deaths were uniformly distributed over the days of the week. She randomly selected 300 pedestrian deaths, recorded the day of the week on which the death occurred, and obtained the following results (th
> Do people cheat or lie when the cheating or lying is not easy to identify (such as filing of taxes)? A total of 2568 college-aged subjects from various countries throughout the world rolled a single six-sided die twice. The subjects were told that the
> A researcher wanted to determine whether bicycle deaths were uniformly distributed over the days of the week. She randomly selected 200 deaths that involved a bicycle, recorded the day of the week on which the death occurred, and obtained the following r
> In his book Outliers, Malcolm Gladwell claims that more hockey players are born in January through March than in October through December. The following data show the number of players in the National Hockey League in the 2018–2019 season according to
> On January 1, 2004, it became mandatory for all police departments in Illinois to record data pertaining to race from every traffic stop. Mundelein, Illinois, has been collecting data since 2000. Rather than using census data to determine the racial dist
> Does the location of your seat in a classroom play a role in attendance or grade? To answer this question, professors randomly assigned 400 students* in a general education physics course to one of four groups. *The number of students was increased so th
> Write a survey question that contains strong wording and one that contains tempered wording. Post each question in an online survey site such as StatCrunch, surveymonkey.com, or polldaddy.com. Administer the survey to at least 25 different people for eac
> Is the religious make-up of the United States Congress reflective of that in the general population? The following table shows the religious affiliation of the 535 members of the 116th Congress along with the religious affiliation of a random sample of 1
> The National Highway Traffic Safety Administration publishes reports about motorcycle fatalities and helmet use. The distribution shows the proportion of fatalities by location of injury for motorcycle accidents. (a) Does the distribution of fatal injuri
> Refer to Problem 13. The distribution in the next column lists the first digit of the surface area (in square miles) of 335 rivers. Is there evidence at the = 0.05 level of significance to support the belief that the distribution follows Benford’s La
> Our number system consists of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. The first significant digit in any number must be 1, 2, 3, 4, 5, 6, 7, 8, or 9 because we do not write numbers such as 12 as 012. Although we may think that each 1 first digit app
> According to the manufacturer of M&Ms, 12% of the peanut M&Ms in a bag should be brown, 15% yellow, 12% red, 23% blue, 23% orange, and 15% green. A student randomly selected a bag of peanut M&Ms. He counted the number of M&Ms that were each color and obt
> According to the manufacturer of M&Ms, 13% of the plain M&Ms in a bag should be brown, 14% yellow, 13% red, 24% blue, 20% orange, and 16% green. A student randomly selected a bag of plain M&Ms. He counted the number of M&Ms that were each color and obtai
> H0: The random variable X is binomial with n = 4, p = 0.3 H1: The random variable X is not binomial with n = 4, p = 0.3
> H0: The random variable X is binomial with n = 4, p = 0.8 H1: The random variable X is not binomial with n = 4, p = 0.8
> H0: pA = pB = pC = pD = pE = 1/5 H1: At least one of the proportions is different from the others.
> H0: pA = pB = pC = pD = 1/4 H1: At least one of the proportions is different from the others.
> In the early 1990s, Gallup asked Americans whether they supported the United States bombing Serbian forces in Bosnia. In this survey, 35% of respondents supported the idea. The very same day, ABC News asked whether Americans would support the United Stat
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> What are the two requirements that must be satisfied to perform a goodness-of-fit test?
> Suppose there are n independent trials of an experiment with k > 3 mutually exclusive outcomes, where pi represents the probability of observing the ith outcome. The______ for each possible outcome are given by Ei =________ .
> The following data represent the measure of a variable before and after a treatment. Does the sample evidence suggest that the treatment is effective in increasing the value of the response variable? Use the = 0.05 level of significance. Note: Assume t
