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Question: The Wall Street Journal reported that the


The Wall Street Journal reported that the age at first startup for 55% of entrepreneurs was 29 years of age or less and the age at first startup for 45% of entrepreneurs was 30 years of age or more.
a. Suppose a sample of 200 entrepreneurs will be taken to learn about the most important qualities of entrepreneurs. Show the sampling distribution of p̅ where p̅ is the sample proportion of entrepreneurs whose first startup was at 29 years of age or less.
b. What is the probability that the sample proportion in part (a) will be within ±.05 of its population proportion?
c. Suppose a sample of 200 entrepreneurs will be taken to learn about the most important qualities of entrepreneurs. Show the sampling distribution of p̅ where p̅ is now the sample proportion of entrepreneurs whose first startup was at 30 years of age or more.
d. What is the probability that the sample proportion in part (c) will be within ±.05 of its population proportion?
e. Is the probability different in parts (b) and (d)? Why?


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> A Bloomberg Businessweek North American subscriber study collected data from a sample of 2861 subscribers. Fifty-nine percent of the respondents indicated an annual income of $75,000 or more, and 50% reported having an American Express credit card. a. Wh

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> The Bureau of Transportation Statistics Omnibus Household Survey is conducted annually and serves as an information source for the U.S. Department of Transportation. In one part of the survey the person being interviewed was asked to respond to the follo

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> The Tennessean, an online newspaper located in Nashville, Tennessee, conducts a daily poll to obtain reader opinions on a variety of current issues. In a recent poll, 762 readers responded to the following question: “If a constitutional amendment to ban

> Consider the following data. a. Construct a dot plot. b. Construct a frequency distribution. c. Construct a percent frequency distribution.

> Many service companies collect data via a follow- up survey of their customers. For example, to ascertain customer sentiment, Delta Air Lines sends an email to customers immediately following a flight. Among other questions, Delta asks: How likely are yo

> J.D. Power and Associates surveys new automobile owners to learn about the quality of recently purchased vehicles. The following questions were asked in a J.D. Power Initial Quality Survey. a. Did you purchase or lease the vehicle? b. What price did you

> Refer to the data set in Table 1.7. a. What is the average price for the phones? b. What is the average talk time for the phones? c. What percentage of the phones have a voice quality of excellent? Table 1.7:

> Table 1.7 shows data for eight phones (Consumer Reports). The Overall Score, a measure of the overall quality for the phone, ranges from 0 to 100. Voice Quality has possible ratings of poor, fair, good, very good, and excellent. Talk Time is the manufac

> Refer to Table 1.6. a. What is the average cost for the tablets? b. Compare the average cost of tablets with a Windows operating system to the average cost of tablets with an Android operating system. c. What percentage of tablets use a CPU manufactured

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> Discuss the differences between statistics as numerical facts and statistics as a discipline or field of study

> The Wall Street Journal provides the net asset value, the year-to-date percent return, and the three-year percent return for 882 mutual funds at the end of 2017. Assume that a simple random sample of 12 of the 882 mutual funds will be selected for a foll

> The following stocks make up the Dow Jones Industrial Average. Suppose you would like to select a sample of six of these companies to conduct an indepth study of management practices. Use the first two digits in each row of the ninth column of Table 7.

> Assume that we want to identify a simple random sample of 12 of the 372 doctors practicing in a particular city. The doctors’ names are available from a local medical organization. Use the eighth column of five-digit random numbers in T

> Construct a histogram for the data in exercise 12. Exercise 12: Consider the following frequency distribution. Class ……………………………….. Frequency 10–19 …………………………………………. 10 20–29 ………………………………………… 14 30–39 …………………………………………. 17 40–49 …………………………………………. 7 50–5

> The County and City Data Book, published by the Census Bureau, lists information on 3139 counties throughout the United States. Assume that a national study will collect data from 30 randomly selected counties. Use four-digit random numbers from the last

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> According to the U.S. Department of Health and Human Services, only 49.2% of homes in the United States used landline telephone service in 2017. a. Suppose a sample of 207,000 U.S. homes will be taken to learn about home telephone usage. Show the samplin

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> Assume that the population proportion is .44. Compute the standard error of the proportion, σp̅, for sample sizes of 500,000; 1,000,000; 5,000,000; 10,000,000; and 100,000,000. What can you say about the size of the standard error of the sample Proportio

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> Consider the following frequency distribution. Class ……………………………….. Frequency 10–19 …………………………………………. 10 20–29 ………………………………………… 14 30–39 …………………………………………. 17 40–49 …………………………………………. 7 50–59 …………………………………………. 2 Construct a cumulative frequency distribut

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> The Wall Street Journal reports that 33% of taxpayers with adjusted gross incomes between $30,000 and $60,000 itemized deductions on their federal income tax return. The mean amount of deductions for this population of taxpayers was $16,642. Assume the s

> In May 2018, The College Board reported the following mean scores for two parts of the Scholastic Aptitude Test (SAT): Assume that the population standard deviation on each part of the test is s = 100. a. What is the probability a sample of 90 test tak

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> Refer to the EAI sampling problem. Suppose a simple random sample of 60 managers is used. a. Sketch the sampling distribution of x̅ when simple random samples of size 60 are used. b. What happens to the sampling distribution of x̅ if simple random sample

> Suppose a random sample of size 50 is selected from a population with σ = 10. Find the value of the standard error of the mean in each of the following cases (use the finite population correction factor if appropriate). a. The population size is infinite

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> Assume a finite population has 350 elements. Using the last three digits of each of the following five-digit random numbers (e.g., 601, 022, 448, . . . ), determine the first four elements that will be selected for the simple random sample.

> A population has a mean of 200 and a standard deviation of 50. Suppose a sample of size 100 is selected and x̅ is used to estimate µ. a. What is the probability that the sample mean will be within ±5 of the population mean? b. What is the probability tha

> A population has a mean of 200 and a standard deviation of 50. A sample of size 100 will be taken and the sample mean x̅ will be used to estimate the population mean. a. What is the expected value of x̅ ? b. What is the standard deviation of x̅ ? c. Show

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> In a sample of 426 U.S. adults age 50 and older, AARP asked how important a variety of issues were in choosing whom to vote for in the next presidential election. a. What is the sampled population for this study? b. Social Security and Medicare was cited

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> Nearly 1.9 million bachelor’s degrees and over 758,000 master’s degrees are awarded annually by U.S. postsecondary institutions as of 2018 (National Center for Education Statistics website). The Department of Education

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> A survey question for a sample of 150 individuals yielded 75 Yes responses, 55 No responses, and 20 No Opinions. a. What is the point estimate of the proportion in the population who respond Yes? b. What is the point estimate of the proportion in the pop

> The following data are from a simple random sample. a. What is the point estimate of the population mean? b. What is the point estimate of the population standard deviation?

> Indicate which of the following situations involve sampling from a finite population and which involve sampling from an infinite population. In cases where the sampled population is finite, describe how you would construct a frame. a. Obtain a sample of

> 1. Consider a finite population with five elements labeled A, B, C, D, and E. Ten possible simple random samples of size 2 can be selected. a. List the 10 samples beginning with AB, AC, and so on. b. Using simple random sampling, what is the probability

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> Using Figure 6.6 as a guide, sketch a normal curve for a random variable x that has a mean of µ = 100 and a standard deviation of σ = 10. Label the horizontal axis with values of 70, 80, 90, 100, 110, 120, and 130. Figure 6.6:

> Suppose we are interested in bidding on a piece of land and we know one other bidder is interested.1 The seller announced that the highest bid in excess of $10,000 will be accepted. Assume that the competitor’s bid x is a random variable that is uniforml

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> Most computer languages include a function that can be used to generate random numbers. In Excel, the RAND function can be used to generate random numbers between 0 and 1. If we let x denote a random number generated using RAND, then x is a continuous ra

> The Boston Fire Department receives 911 calls at a mean rate of 1.6 calls per hour (Mass.gov website). Suppose the number of calls per hour follows a Poisson probability distribution. a. What is the mean time between 911 calls to the Boston Fire Departme

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> Comcast Corporation is a global telecommunications company headquartered in Philadelphia, PA. Generally known for reliable service, the company periodically experiences unexpected service interruptions. When service interruptions do occur, Comcast custom

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> Battery life between charges for a certain mobile phone is 20 hours when the primary use is talk time, and drops to 7 hours when the phone is primarily used for Internet applications over a cellular network. Assume that the battery life in both cases fol

> Consider the following exponential probability density function. f (x) = 1/3 e-x/3 for x ≥ 0 a. Write the formula for P(x ≤ x0). b. Find P(x ≤ 2). c. Find P(x ≥ 3). d. Find P(x ≤ 5). e. Find P(2 ≤ x ≤ 5).

> Consider the following exponential probability density function. f (x) = 1/8 e-x /8 for x ≥ 0 a. Find P(x ≤ 6). b. Find P(x ≤ 4). c. Find P(x ≥ 6). d. Find P(4 ≤ x ≤ 6).

> Rocky Mountain National Park is a popular park for outdoor recreation activities in Colorado. According to U.S. National Park Service statistics, 46.7% of visitors to Rocky Mountain National Park in 2018 entered through the Beaver Meadows park entrance,

> Many airlines use surveys to collect data on customer satisfaction related to flight experiences. Completing a flight, customers receive an email asking them to rate a variety of factors, including the reservation process, the check-in process, luggage p

> Suppose that of those individuals who play video and computer games, 18% are under 18 years old, 53% are 18–59 years old, and 29% are over 59 years old. Use the normal approximation of the binomial distribution to answer the questions below. a. For a sam

> Delta Airlines quotes a flight time of 2 hours, 5 minutes for its flights from Cincinnati to Tampa. Suppose we believe that actual flight times are uniformly distributed between 2 hours and 2 hours, 20 minutes. a. Show the graph of the probability densit

> According to a Yale program on climate change communication survey, 71% of Americans think global warming is happening (American Psychological Association website). a. For a sample of 15 Americans, what is the probability that at least 12 believe global

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