2.99 See Answer

Question: The article “Younger adults more Likely than


The article “Younger adults more Likely than their elders to prefer reading the news” (October 6, 2016, www .pewresearch.org/fact-tank/2016/10/06/younger-adults -more-likely-than-their-elders-to-prefer-reading-news/) estimated that only 3% of those age 65 and older who prefer to watch the news, rather than to read or listen, watch the news online. This estimate was based on a survey of a large sample of adult Americans conducted by the Pew Research Center. Consider the population consisting of all adult Americans age 65 and older who prefer to watch the news and suppose that for this population the actual proportion who prefer to watch online is 0.03.
a. A random sample of n = 100 people will be selected from this population and pˆ, the proportion of people who prefer to watch online, will be calculated. What are the mean and standard deviation of the sampling distribution of pˆ?
b. Is the sampling distribution of pˆ approximately normal for random samples of size n 5 100? Explain.
c. Suppose that the sample size is n = 400 rather than n = 100. Does the change in sample size affect the mean and standard deviation of the sampling distribution of pˆ? If so, what are the new values for the mean and standard deviation? If not, explain why not.
d. Is the sampling distribution of pˆ approximately normal for random samples of size n = 400? Explain.


> 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

> The article “facebook etiquette at work” (USA TODAY, March 24, 2010) reported that 56% of people participating in a survey of social network users said it was not OK for someone to “friend” his or her boss. Let p denote the proportion of all social netwo

> For which of the population proportions given in the previous exercise would the sampling distribution of pˆ be approximately normal if n = 40? If n = 75?

> A random sample of size 300 is to be selected from a population. Determine the mean and standard deviation of the sampling distribution of pˆ for each of the following population proportions. a. p = 0.20 b. p = 0.45 c. p = 0.70 d. p = 0.90

> For which of the following sample sizes would the sampling distribution of pˆ be approximately normal when p = 0.2? When p = 0.8? When p = 0.6? n = 10 n = 25 n = 50 n = 100

> Explain why the standard deviation of pˆ is equal to 0 when the population proportion is equal to 1.

> For which of the following combinations of sample size and population proportion would the standard deviation of pˆ be smallest? n = 40 p = 0.3 n = 60 p = 0.4 n = 100 p = 0.5

> The U.S. Census Bureau reported that in 2015 the proportion of adult Americans age 25 and older who have a bachelor’s degree or higher is 0.325 (“educational attainment in the United States: 2015,” www.census.gov, retrieved January 22, 2017). Consider th

> A certain chromosome defect occurs in only 1 in 200 adult Caucasian males. A random sample of 100 adult Caucasian males will be selected. The proportion of men in this sample who have the defect, pˆ, will be calculated. a. What are the mean and standard

> For which of the sample sizes given in the previous exercise would the sampling distribution of pˆ be approximately normal if p = 0.25? If p = 0.6?

> A random sample is to be selected from a population that has a proportion of successes p = 0.25. 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.

> The article referenced in the previous exercise also reported that for people age 18 to 29 who prefer to watch the news, the proportion that prefer to watch online is 0.37. Answer the questions posed in Parts (a)–(d) of the previous exercise for the popu

> For which of the sample sizes given in the previous exercise would the sampling distribution of p ˆ be approximately normal if p = 0.65? If p = 0.2?

> A random sample is to be selected from a population that has a proportion of successes p = 0.65. 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: A county tax assessor reported that the proportion of property owners who paid 2016 property taxes on time was 0.93. a. Is the number that appears in boldface in this statement a sample proportion or a population propor

> Consider the following statement: In a sample of 20 passengers selected from those who flew from Dallas to New York City in April 2017, the proportion who checked luggage was 0.45. a. Is the number that appears in boldface in this statement a sample pro

> Consider the two relative frequency histograms at the top of the next page. The histogram on the left was constructed by selecting 100 different random samples of size 35 from a population in which 17% donated to a nonprofit organization. For each sample

> Explain what it means when we say the value of a sample statistic varies from sample to sample.

> Consider the following statement: The proportion of all calls made to a county 9-1-1 emergency number during the year 2017 that were nonemergency calls was 0.14. a. Is the number that appears in boldface in this statement a sample proportion or a popula

> Consider the following statement: Fifty people were selected at random from those attending a football game. The proportion of these 50 who made a food or beverage purchase while at the game was 0.83. a. Is the number that appears in boldface in this st

> Explain what the term sampling variability means in the context of using a sample proportion to estimate a population proportion.

> Consider the two relative frequency histograms at the top of the next page. The histogram on the left was constructed by selecting 100 different random samples of size 40 from a population consisting of 20% part-time students and 80% full-time students.

> A random sample of 100 employees of a large company included 37 who had worked for the company for less than one year. For this sample, pˆ = 37 = 0.37. If a different 100 random sample of 100 employees were selected, would you expect that

> Explain the difference between p and pˆ.

> Consider the following statement: A sample of size 100 was selected from those admitted to a particular college in fall 2017. The proportion of these 100 who were transfer students is 0.38. a. Is the number that appears in boldface in this statement a s

> Consider the following statement: The Department of Motor Vehicles reports that the proportion of all vehicles registered in California that are imports is 0.22. a. Is the number that appears in boldface in this statement a sample proportion or a popula

> Consider the two relative frequency histograms at the bottom of this page. The histogram on the left was constructed by selecting 100 different random samples of size 50 from a population consisting of 55% females and 45% males. For each sample, the samp

> A random sample of 1000 students at a large college included 428 who had one or more credit cards. For this sample, pˆ = 428 = 0.428. If another random sample of 1000 students from 1000 this university were selected, would you expect

> The process for statistical inference described in Section 7.3 consists of five steps: a. What are the five steps in the process for estimation problems? b. Explain how the first step differs for estimation problems and hypothesis testing problems.

> The authors of the paper “flat-footedness is not a Disadvantage for athletic Performance in children aged 11 to 15 Years” (Pediatrics [2009]: e386–e392) collected data from 218 children on foot arch h

> In a study to determine if using low-intensity laser therapy reduces pain for orthodontic patients who are fitted with new braces, patients were randomly assigned to either a control group (who did not receive laser treatment) and an experimental group w

> Refer to the instructions prior to this exercise. A study of adult Americans conducted by the polling organization Ipsos (“One in Five Americans Consider Themselves ‘Entrepreneurs,’”

> Explain why the question T: Type of data—one variable or two? Categorical or numerical? is one of the four key questions used to guide decisions about what inference method should be considered.

> Suppose that a study was carried out in which each student in a random sample of students at a particular college was asked if he or she was registered to vote. Would these data be used to estimate a population mean or to estimate a population proportion

> In a study of whether taking a garlic supplement reduces the risk of getting a cold, 146 participants were randomly assigned to either a garlic supplement group or to a group that did not take a garlic supplement (“Garlic for the Common Cold,” Cochrane D

> In the paper “happiness for Sale: Do experiential purchases make consumers happier than material purchases?” (Journal of Consumer Research [2009]: 188–197), the authors distinguish between spending mo

> If you deposit a $20 bill into a checking account and your bank has a 10 percent reserve requirement, by how much will the bank’s excess reserves rise?

> Briefly describe the effect on the money supply of the following monetary policies: a. The Fed purchases $20 million worth of U.S. Treasury bonds. b. The Fed increases the discount rate. c. The Fed decreases the discount rate. d. The Fed sells $40 millio

> Should the Fed be independent or a government agency subordinate to Congress and the president?

> Distinguish between M1 and M2. What are near monies?

> What backs the U.S. dollar? Include the distinction between commodity money and fiat money in your answer.

> Could each of the following items potentially serve as money? Consider each as a medium of exchange, a unit of account, or a store of value. a. Visa credit card. b. Federal Reserve note. c. Debit card. d. Picasso painting.

> Briefly discuss the importance of the Depository Institutions Deregulation and Monetary Control Act of 1980.

> Suppose the media report that the federal deficit this year is $200 billion. The national debt was $5,000 billion last year, and it is $5,200 billion this year. The price level this year is 3 percent higher than it was last year. What is the real deficit

> Explain the theory that crowding out can weaken or nullify the effect of expansionary fiscal policy financed by federal government borrowing.

> Explain this statement: “The most unlikely problem of the national debt is that the government will go bankrupt.”

> The following is a set of hypothetical production possibilities for a nation. a. Plot these production possibilities data. What is the opportunity cost of the first 2,000 automobiles produced? Between which points is the opportunity cost per thousand a

> Discuss various ways of measuring the size of the national debt.

> Consider this statement: “Our grandchildren may not suffer the entire burden of a federal deficit.” Do you agree or disagree? Explain.

> Explain why each of the following taxes is progressive or regressive. a. A $1 per pack federal excise tax on cigarettes. b. The federal individual income tax. c. The federal payroll tax.

> Explain why a 5 percent sales tax on gasoline is regressive.

> Which of the following taxes satisfy the benefits received principle, and which satisfy the ability to pay principle? a. Gasoline tax b. Federal income tax c. Tax on Social Security benefits

> What are the four largest categories of expenditures of the federal government?

> Calculate the average and marginal tax rates in the following table, and indicate whether the tax is progressive, proportional, or regressive. What observation can you make concerning the relationship between marginal and average tax rates? Average

> What is the difference between discretionary fiscal policy and automatic stabilizers? How are federal budget surpluses and deficits affected by the business cycle?

> Consider an economy that is operating at the full employment level of real GDP. Assuming the MPC is 0.90, predict the effect on the economy of a $50 billion increase in government spending balanced by a $50 billion increase in taxes.

> Why does a reduction in taxes have a smaller multiplier effect than an increase in government spending of an equal amount?

> Analyze the positive versus normative arguments in the following case. What statements of positive economics are used to support requiring air bags? What normative reasoning is used?

> How does each of the following affect the aggregate demand curve? a. Government spending increases. b. The amount of taxes collected decreases.

> Suppose Congress enacts a tax reform law and the average federal tax rate drops from 30 percent to 20 percent. Researchers investigate the impact of the tax cut and find that the income subject to the tax increases from $600 billion to $800 billion. The

> In the first quarter of 2001, real GDP was $9.88 trillion, and the price level measured by the GDP chain price index was 101. Real GDP was approximately equal to potential GDP. In the third quarter, aggregate demand decreased to $9.83 trillion, and the p

> Based on the assumptions of Question 3, explain verbally the impact of an increase of $4 trillion in aggregate demand on short-run equilibrium.

> Using the graph from Question 1 and assuming long run equilibrium at $12 trillion, explain the impact of a 10 percent increase in workers’ income.

2.99

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