Give an example of a situation where it would be appropriate to use a chi-square test of independence. Describe the population that would be sampled and the two variables that would be recorded.
> Give as much information as you can about the P-value for an upper-tailed F test in each of the following situations. a. df1 = 4, df2 = 15, F = 5.37 b. df1 = 4, df2 = 15, F = 1.90 c. df1 = 4, df2 = 15, F = 4.89 d. df1 = 3, df2 = 20, F = 14.48 e. df1
> The paper “patterns and composition of weight change in college freshmen” (College Student Journal [2015]: 553–564) reported that the freshman year weight gain for the students in a representative sample of 103 freshmen at a midwestern university was 5.7
> The Bureau of Alcohol, Tobacco, and Firearms (ATF) has been concerned about lead levels in California wines. In a previous testing of wine specimens, lead levels ranging from 50 to 700 parts per billion were recorded. How many wine specimens should be te
> The paper referenced in the previous exercise also reported that for a representative sample of 68 second-year students at the university, the sample mean procrastination score was 41.00 and the sample standard deviation was 6.82. a. Construct a 95% con
> Students in a representative sample of 65 first-year students selected from a large university in England participated in a study of academic procrastination (“Study goals and procrastination tendencies at Different Stages of the Undergraduate Degree,” S
> The paper “the effects of adolescent Volunteer activities on the perception of Local Society and community Spirit mediated by Self-conception” (Advanced Science and Technology Letters [2016]: 19–23) describes a survey of a large representative sample of
> The two intervals (114.4, 115.6) and (114.1, 115.9) are confidence intervals for µ = mean resonance frequency (in hertz) for all tennis rackets of a certain type. The two intervals were calculated using the same sample data. a. What is the value of the
> The formula used to calculate a confidence interval for the mean of a normal population is What is the appropriate t critical value for each of the following confidence levels and sample sizes? a. 95% confidence, n = 17 b. 99% confidence, n = 24 c. 90
> What percentage of the time will a variable that has a t distribution with the specified degrees of freedom fall in the indicated region? (Hint: See discussion on page 581.) a. 10 df, between -1.81 and 1.81 b. 24 df, between -2.06 and 2.06 c. 24 df,
> An airplane with room for 100 passengers has a total baggage limit of 6000 pounds. Suppose that the weight of baggage checked by an individual passenger, x, has a mean of 50 pounds and a standard deviation of 20 pounds. If 100 passengers will board a fli
> A manufacturing process is designed to produce bolts with a diameter of 0.5 inches. Once each day, a random sample of 36 bolts is selected and the bolt diameters are recorded. If the resulting sample mean is less than 0.49 inches or greater than 0.51 inc
> Suppose that a random sample of size 100 is to be drawn from a population with standard deviation 10. a. What is the probability that the sample mean will be within 20 of the value of m? b. F or this example (n = 100, σ = 10), complete each of the foll
> Suppose that the population mean value of interpupillary distance (the distance between the pupils of the left and right eyes) for adult males is 65 mm and that the population standard deviation is 5 mm. a. If the distribution of interpupillary distance
> A sign in the elevator of a college library indicates a limit of 16 persons. In addition, there is a weight limit of 2500 pounds. Assume that the average weight of students, faculty, and staff at this college is 150 pounds, that the standard deviation is
> Explain the difference between x and µ x.
> For which of the sample sizes given in the previous exercise would it be reasonable to think that the sampling distribution of x is approximately normal in shape?
> A random sample is selected from a population with mean µ = 200 and standard deviation σ = 15. Determine the mean and standard deviation of the sampling distribution of x for each of the following sample sizes: a. n = 12 b. n = 20 c. n = 25 d. n = 40
> Suppose that a random sample of size 64 is to be selected from a population with mean 40 and standard deviation 5. a. What are the mean and standard deviation of the sampling distribution of x? Describe the shape of the sampling distribution of x? b. Wh
> Explain the difference between σ and σx.
> The paper “alcohol consumption, Sleep, and academic performance among college Students” (Journal of Studies on Alcohol and Drugs [2009]: 355–363) describes a study of n = 236 students that were random
> For which of the sample sizes given in the previous exercise would it be reasonable to think that the x sampling distribution is approximately normal in shape?
> A random sample is selected from a population with mean µ = 60 and standard deviation σ = 3. Determine the mean and standard deviation of the sampling distribution of x for each of the following sample sizes: a. n = 6 b. n = 18 c. n = 42 d. n = 75 e
> The time that people have to wait for an elevator in an office building has a uniform distribution over the interval from 0 to 1 minute. For this distribution, µ = 0.5 and σ = 0.289. a. If x is the average waiting time for a random sample of n = 16 wait
> Explain the difference between µ and µx.
> The paper “alcohol consumption, Sleep, and academic performance among college Students” ( Journal of Studies on Alcohol and Drugs [2009]: 355–363) describes a study of n = 236 students who were random
> For which of the sample sizes given in the previous exercise would it be reasonable to think that the x sampling distribution is approximately normal in shape?
> A random sample is selected from a population with mean µ = 100 and standard deviation σ = 10. Determine the mean and standard deviation of the sampling distribution of x for each of the following sample sizes: a. n = 9 b. n = 15 c. n = 36 d. n = 50
> The press release titled “Nap Time” (July 2009, pewresearch. org, retrieved May 27, 2017) described results from a nationally representative survey of 1488 adult Americans. The survey asked several demographic question
> The paper referenced in the previous exercise also included the accompanying data on how often students said they had consumed fried potatoes (French fries or potato chips) in the past week. Use the accompanying Minitab output to carry out a chi-square
> The following passage is from the paper “Gender Differences in Food Selections of Students at a Historically Black College and University” (College Student Journal [2009]: 800–806): Also significant was the proportion of males and their water consumption
> The report “Consumer Revolving Credit and Debt Over the Life Cycle and Business Cycle” describes a study conducted by the Federal Reserve Bank of Boston (www.bostonfed. org, October 2015, retrieved May 27, 2017). Data
> The report “Education Pays 2016” (The College Board, trends.collegeboard.org/sites/default/files/education-pays -2016-full-report.pdf, retrieved May 27, 2017) provided information on education level and earnings for a
> The authors of the paper “Movie Character Smoking and Adolescent Smoking: Who Matters More, Good Guys or Bad Guys?” (Pediatrics [2009]: 135–141) studied characters who were depicted smoking in movies
> The accompanying data on degree of spirituality for a random sample of natural scientists and a random sample of social scientists working at research universities appeared in the paper “Conflict Between Religion and Science Among Acade
> In a study of high-achieving high school graduates, the authors of the report “High-Achieving Seniors and the College Decision” (Lipman Hearne, October 2009) surveyed 828 high school graduates who were considered &acir
> The report referenced in the previous two exercises also classified 817 fatal bicycle accidents according to the month in which the accidents occurred, resulting in the accompanying table. a. To determine if some months are riskier than others, use the
> Suppose a safety officer proposes that bicycle fatalities are twice as likely to occur between noon and midnight as during midnight to noon and suggests the following hypothesis: /where p1 is the proportion of accidents occurring between midnight and noo
> The report “Fatality Facts 2004: Bicyclists 2015” (Insurance Institute, 2015, www.iihs.org/iihs/topics/t/pedestrians-and-bicyclists/fatalityfacts/bicycles, retrieved May 27, 2017) included the following table classifyi
> The authors of the paper “Racial Stereotypes in Children’s Television Commercials” ( Journal of Advertising Research [2008]: 80–93) counted the number of times that characters of dif
> Jail inmates can be classified into one of the following four categories according to the type of crime committed: violent crime, crime against property, drug crime, and public-order offenses. Suppose that random samples of 500 male inmates and 500 femal
> The authors of the paper “Risk of Malnutrition Is an Independent Predictor of Mortality, Length of Hospital Stay, and Hospitalization Costs in Stroke Patients” (Journal of Stroke and Cerebrovascular Diseases [2016]: 79
> The report referenced in the previous exercise also provided data on perception of money management skills by age group. Use the data from 788 people in the accompanying table to determine if there is evidence of an association between age and perception
> The report “Majoring in Money: How American College Students Manage Their Finances” (June 28, 2016, salliemae.newshq.businesswire.com/sites/salliemae.newshq.businesswire .com/files/doc_library/file/SallieMae_Majoringin
> Does viewing angle affect a person’s ability to tell the difference between a female nose and a male nose? This important (?) research question was examined in the article “You Can Tell by the Nose: Judging Sex from an
> Each person in a representative sample of 445 college students age 18 to 24 was classified according to age and to the response to the following question: “How often have you used a credit card to buy items knowing you wouldnâ
> The report “Smartphone Ownership and Internet Usage Continues to Climb in Emerging Economies” (Pew Research Center, February 22, 2016, www.pewglobal .org/2016/02/22/smartphone-ownership-and-internet -usage-continues-to
> Are babies born to mothers who use assistive reproduction technology (ART) more likely to be born prematurely than babies conceived naturally? The data in the accompanying table are from the paper “Child Growth from Birth to 18 Months A
> Explain the difference between situations that would lead to a chi-square test for homogeneity and those that would lead to a chi-square test for independence.
> Explain the difference between situations that would lead to a chi-square goodness-of-fit test and those that would lead to a chi-square test of homogeneity.
> Give an example of a situation where it would be appropriate to use a chi-square test of homogeneity. Describe the populations that would be sampled and the variable that would be recorded.
> Each person in a large sample of German adolescents was asked to indicate which of 50 popular movies he or she had seen in the past year. Based on the response, the amount of time (in minutes) of alcohol use contained in the movies the person had watched
> The paper “Contemporary College Students and Body Piercing” (Journal of Adolescent Health [2004]: 58–61) described a survey of 490 undergraduate students at a state university in the southwestern regi
> The Knight Foundation investigated whether high school students agreed with the statement that people should be allowed to burn or deface the American flag as a political statement. This question was asked in a survey of a representative sample of high s
> The data in the accompanying table are from the paper “Gender Differences in Food Selections of Students at a Historically Black College and University” (College Student Journal [2009]: 800–806). Supp
> The paper “Credit Card Misuse, Money Attitudes, and Compulsive Buying Behavior: Comparison of Internal and External Locus of Control Consumers” (College Student Journal [2009]: 268–275) describes a su
> The authors of the paper “The Relationship of Field of Study to Current Smoking Status Among College Students” (College Student Journal [2009]: 744–754) carried out a study to investigate if smoking r
> The Knight Foundation asked each person in a representative sample of high school students and in a representative sample of high school teachers which of the rights guaranteed by the First Amendment they thought was the most important (â€
> Some colleges now allow students to pay their tuition using a credit card. The report “Credit Card Tuition Payment Survey 2014” (www.creditcards.com/credit-card -news/tuition-charge-fee-survey.php, retrieved May 27, 20
> The authors of the paper “External Factors and the Incidence of Severe Trauma: Time, Date, Season and Moon” (Injury [2014]: S93–S99) classified admissions to hospitals in Germany according to season.
> Birds use color to select and avoid certain types of food. The authors of the article “Colour Avoidance in Northern Bobwhites: Effects of Age, Sex, and Previous Experience” (Animal Behaviour [1995]: 519â€
> Suppose that each observation in a random sample of 100 fatal bicycle accidents in 2015 was classified according to the day of the week on which the accident occurred. Data consistent with information on the Insurance Institute for Highway Safety website
> The article “Linkage Studies of the Tomato” (Transactions of the Royal Canadian Institute [1931]: 1–19) reported the accompanying data on phenotypes resulting from crossing tall cut-leaf tomatoes with
> A certain genetic characteristic of a particular plant can appear in one of three forms (phenotypes). A researcher has developed a theory, according to which the hypothesized proportions are p1 = 0.25, p2 = 0.50, and p3 = 0.25. A random sample of 200 pla
> Think about how you would answer the following question. Next Wednesday’s meeting has been moved forward two days. What day is the meeting now that it has been rescheduled? This question is ambiguous, as “moved forwa
> For which of the X 2 and df pairs in the previous exercise would the null hypothesis be rejected if a significance level of = 0.01 were used?
> What is the approximate P-value for the following values of X 2 and df? a. X 2 = 34.52, df = 13 b. X 2 = 39.25, df = 16 c. X 2 = 26.00, df = 19
> A popular urban legend is that more babies than usual are born during certain phases of the lunar cycle, especially near the full moon. The paper “The Effect of the Gravitation of the Moon on Frequency of Births” (Envi
> The “Global Automotive 2016 Color Popularity Report” (Axalta Coating Systems, www.axaltacs.com, retrieved May 27, 2017) included data on the colors for a sample of new cars sold in North America. The report stated that 25% of the cars in the sample were
> The authors of the paper “Talking Smack: Verbal Aggression in Professional Wrestling” (Communication Studies [2008]: 242–258) analyzed the content of 36 hours of televised professional wrestling. Each
> Packages of mixed nuts made by a certain company contain four types of nuts. The percentages of nuts of Types 1, 2, 3, and 4 are advertised to be 40%, 30%, 20%, and 10%, respectively. A random sample of nuts is selected, and each one is categorized by ty
> What is the approximate P-value for the following values of X 2 and df? a. X 2 = 14.44, df = 6 b. X 2 = 16.91, df = 9 c. X 2 = 32.32, df = 20
> In 2014, the University of Houston carried out a study for the Texas Lottery Commission (“Demographic Survey of Texas Lottery Players,” www.uh.edu/class/hobby/_docs /Texas%20Lottery%20Study%202014.pdf, retrieved May 27
> The article “In Bronx, Hitting Home Runs Is a Breeze” (USA TODAY, June 2, 2009) included a classification of 87 home runs hit at the new Yankee Stadium according to the direction that the ball was hit, resulting in the
> The authors of the paper “Is It Really About Me? Message Content in Social Awareness Streams” (Computer Supported Cooperative Work 2010) studied a random sample of 350 Twitter users. For each Twitter user in the sample
> What is the approximate P-value for the following values of X 2 and df? a. X 2 = 6.62, df = 3 b. X 2 = 16.97, df = 10 c. X 2 = 30.19, df = 17
> A particular cell phone case is available in a choice of four different colors. A store sells all four colors. To test the hypothesis that sales are equally divided among the four colors, a random sample of 100 purchases is identified. a. If the resulti
> The article “an alternative Vote: applying Science to the teaching of Science” (The Economist, may 12, 2011) describes an experiment conducted at the University of British Columbia. A total of 850 engineering students enrolled in a physics course partici
> In a survey of a representative sample of adults in the United States, participants were asked if they agreed or disagreed with the statement “I can’t imagine my life without my smartphone” (july 13,
> Suppose that the actual proportion of students at a particular college who use public transportation to travel to campus is 0.15. In a study of parking needs at the campus, college administrators would like to estimate this proportion. They plan to take
> The company Digital Trends reported that 48% of Americans have shared passwords for TV and movie streaming (“americans Know they Shouldn't Share their passwords, but Do it anyway,” february 18, 2016, www.digitaltrends.com /computing/everyone-shares-passw
> The article “fewer americans are reading, but Don't blame the millennials” (Los Angeles Times, october 9, 2016) indicates that 80% of millennials (those age 18–29) have read a book in the last year. Suppose that this is the actual percentage for the popu
> For which of the sample sizes given in the previous exercise would the sampling distribution of pˆ be approximately normal if p = 0.70? If p = 0.30?
> A random sample will be selected from a population that has a proportion of successes p = 0.70. Determine the mean and standard deviation of the sampling distribution of pˆ for each of the following sample sizes: a. n = 10 b. n = 20 c. n = 30 d.
> Consider the following statement: The proportion of all students enrolled at a particular university during 2017 who lived on campus was 0.21. a. Is the number that appears in boldface in this statement a sample proportion or a population proportion? b
> Consider the following statement: An inspector selected 20 eggs at random from the eggs processed at a large egg production facility. These 20 eggs were tested for salmonella, and the proportion of the eggs that tested positive for salmonella was 0.05.
> Explain why there is sample-to-sample variability in pˆ but not in p.
> Consider the following three relative frequency histograms. Each histogram was constructed by selecting 100 random samples from a population composed of 40% women and 60% men. For each sample, the sample proportion of women, pˆ, was calculated
> A random sample of 50 registered voters in a particular city included 32 who favored using city funds for the construction of a new recreational facility. For this sample, pˆ= 32 = 0.64. If a 50 second random sample of 50 registered voters w
> The article referenced in the previous exercise also reported that 38% of the 1200 social network users surveyed said it was OK to ignore a coworker’s friend request. If pˆ = 0.38 is used as an estimate of the proportion of all social network users who b
> The article “facebook etiquette at work” (USA TODAY, march 24, 2010) reported that 56% of 1200 social network users surveyed indicated that they thought it was not OK for someone to “friend” his or her boss. Suppose that this sample can be regarded as a
> In a study of pet owners, it was reported that 24% celebrate their pet’s birthday (Pet Statistics, bissell homecare, inc., 2010). Suppose that this estimate was based on a random sample of 200 pet owners. Is it reasonable to conclude that the proportion
> Some colleges now allow students to rent textbooks for a semester. Suppose that 38% of all students enrolled at a particular college would rent textbooks if that option were available to them. If the campus bookstore uses a random sample of size 100 to e
> The report “a crisis in civic education” (january 2016, goacta.org/images/download/a_crisis_in_civic_education .pdf, retrieved may 3, 2017) indicated that in a survey of a random sample of 1000 recent college graduates, 96 indicated that they believed th
> The article “60% of employers are peeking into candidates’ Social media profiles” (careerbuilders, april 28, 2016, nscresearchcenter.org/wp-content/uploads/Snapshotreport17 -2Yearcontributions.pdf, retrieved october 9, 2016) included data from a survey o
> The article “cSi effect has juries wanting more evidence” (USA TODAY, august 5, 2004) examines how the popularity of crime-scene investigation television shows is influencing jurors’ expectations of w
> Suppose that 20% of the customers of a cable television company watch the Shopping Channel at least once a week. The cable company does not know the actual proportion of all customers who watch the Shopping Channel at least once a week and is trying to d
> The report “the role of two-Year institutions in fourYear Success” (national Student clearinghouse research center, 2015, nscresearchcenter.org/wp-content/uploads /Snapshotreport17-2Yearcontributions.pdf, retrieved may 3, 2017) states that nationwide, 46
> The article “Long-term effects of tongue piercing—a case-control Study” (Clinical Oral Investigations [2012]: 231– 237) describes a study of 46 males with pierced tongues. Suppose that it is reasonable to regard this sample as a random sample from the po
> The article “the average american is in credit card Debt, no matter the economy” (Money Magazine, february 9, 2016) reported that only 35% of credit card users pay off their bill every month. Suppose that the reported
> Suppose that a particular candidate for public office is favored by 48% of all registered voters in the district. A polling organization will take a random sample of 500 of these voters and will use pˆ, the sample proportion, to estimate p. a. Show that
