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 standard deviation is s 5 $2400. a. What is the probability that a sample of taxpayers from this income group who have itemized deductions will show a sample mean within $200 of the population mean for each of the following sample sizes: 30, 50, 100, and 400? b. What is the advantage of a larger sample size when attempting to estimate the population mean?
> The following data were used to construct the histograms of the number of days required to fill orders for Dawson Supply, Inc., and J.C. Clark Distributors Use the range and standard deviation to support the previous observation that Dawson Supply prov
> The Los Angeles Times regularly reports the air quality index for various areas of Southern California. A sample of air quality index values for Pomona provided the following data: 28, 42, 58, 48, 45, 55, 60, 49, and 50. a. Compute the range and interqua
> Annual revenue for Corning Supplies grew by 5.5% in 2014, 1.1% in 2015, −3.5% in 2016, −1.1% in 2017, and 1.8% in 2018. What is the mean growth annual rate over this period?
> Based on a survey of master’s programs in business administration, magazines such as U.S. News & World Report rank U.S. business schools. These types of rankings are based in part on surveys of business school deans and corporate re
> The grade point average for college students is based on a weighted mean computation. For most colleges, the grades are given the following data values: A (4), B (3), C (2), D (1), and F (0). After 60 credit hours of course work, a student at State Unive
> Consider a sample with data values of 10, 20, 12, 17, and 16. Compute the mean and median.
> Consider a sample with data values of 10, 20, 12, 17, and 16. Compute the variance and standard deviation.
> Consider a sample with data values of 10, 20, 12, 17, and 16. Compute the range and interquartile range.
> A survey conducted by Better Homes and Gardens Real Estate LLC showed that one in five U.S. homeowners has either moved from their home or would like to move because their neighborhood or community isn’t ideal for their lifestyle (Better Homes and Garden
> Construct a stem-and-leaf display for the following data. Use a leaf unit of 10.
> Construct a stem-and-leaf display for the following data.
> Construct a histogram for the data in exercise 12. Data from exercise 12:
> Consider the following data. a. Develop a frequency distribution using classes of 12–14, 15–17, 18–20, 21–23, and 24–26. b. Develop a relative frequency distribut
> A random telephone survey of 1021 adults (aged 18 and older) was conducted by Opinion Research Corporation on behalf of CompleteTax, an online tax preparation and e-filing service. The survey results showed that 684 of those surveyed planned to file thei
> A manager of a large corporation recommends a $10,000 raise be given to keep a valued subordinate from moving to another company. What internal and external sources of data might be used to decide whether such a salary increase is appropriate?
> Skechers U.S.A., Inc., is a performance footwear company headquartered in Manhattan Beach, California. The sales revenue for Skechers over a four-year period are as follows: Are these cross-sectional or time-series data? b. Construct a bar graph similar
> Jewelry Sales. The U.S. Census Bureau tracks sales per month for various products and services through its Monthly Retail Trade Survey. Figure 1.9 shows monthly jewelry sales in millions of dollars for 2016. a. Are the data quantitative or categorical?
> Consider the following data. a. Construct a dot plot. b. Construct a frequency distribution. c. Construct a percent frequency distribution.
> Figure 1.8 provides a bar chart showing the annual advertising revenue for Facebook from 2010 to 2017 (Facebook Annual Reports). a. What is the variable of interest? b. Are the data categorical or quantitative? c. Are the data time series or cross-sect
> A seven-year medical research study reported that women whose mothers took the drug diethylstilbestrol (DES) during pregnancy were twice as likely to develop tissue abnormalities that might lead to cancer as were women whose mothers did not take the drug
> Consider the following frequency distribution. Construct a cumulative frequency distribution and a cumulative relative frequency distribution.
> A Gallup Poll utilizing a random sample of 1,503 adults ages 18 or older was conducted in April 2018. The survey indicated a majority of Americans (53%) say driverless cars will be common in the next 10 years (Gallup, https://news.gallup.com/poll/234152/
> The response to a question has three alternatives: A, B, and C. A sample of 120 responses provides 60 A, 24 B, and 36 C. Show the frequency and relative frequency distributions.
> Based on data from the U.S. Census Bureau, a Pew Research study showed that the percentage of employed individuals ages 25–29 who are college educated is at an all-time high. The study showed that the percentage of employed individuals aged 25–29 with at
> 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
> 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
> 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
> The president of Colossus.com, Inc., believes that 42% of the firm’s orders come from customers who have purchased from Colossus.com in the past. A random sample of 108,700 orders from the past six months will be used to estimate the proportion of orders
> The New York Times reported that 17.2 million new cars and light trucks were sold in the United States in 2017, and the U.S. Environmental Protection Agency projects the average efficiency for these vehicles to be 25.2 miles per gallon. Assume that that
> The U.S. Bureau of Labor Statistics (BLS) reported that the mean annual number of hours of vacation time earned by blue-collar and service employees who work for small private establishments and have at least 10 years of service is 100. Assume that for t
> A survey of 131 investment managers in Barron’s Big Money poll revealed the following: ●● 43% of managers classified themselves as bullish or very bullish on the stock market. ●● The average expected return over the next 12 months for equities was 11.2%.
> Tablet PC Comparison provides a wide variety of information about tablet computers. The company’s website enables consumers to easily compare different tablets using factors such as cost, type of operating system, display size, battery
> A sample of size 100,000 is selected from a population with p 5 .75. a. What is the expected value of /? b. What is the standard error of /? c. Show the sampling distribution of /. d. What does the sampling distribution of / show?
> Assume the population standard deviation is σ=25. Compute the standard error of the mean, , 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 mean as the sample s
> A population has a mean of 400 and a standard deviation of 100. A sample of size 100,000 will be taken, and the sample mean / will be used to estimate the population mean. a. What is the expected value of /? b. What is the standard deviation of /? c. Sho
> The Food Marketing Institute shows that 17% of households spend more than $100 per week on groceries. Assume the population proportion is p = .17 and a sample of 800 households will be selected from the population. a. Show the sampling distribution of ,
> The Grocery Manufacturers of America reported that 76% of consumers read the ingredients listed on a product’s label. Assume the population proportion is p = .76 and a sample of 400 consumers is selected from the population. a. Show the sampling distribu
> In 2016 the Better Business Bureau settled 80% of complaints they received in the United States. Suppose you have been hired by the Better Business Bureau to investigate the complaints they received this year involving new car dealers. You plan to select
> In 2017, the Restaurant Hospitality website reported that only 10% of surplus food is being recovered in the food-service and restaurant sector, leaving approximately 1.5 billion meals per year uneaten. Assume this is the true population proportion and t
> 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
> The president of Doerman Distributors, Inc., believes that 30% of the firm’s orders come from first-time customers. A random sample of 100 orders will be used to estimate the proportion of first-time customers. a. Assume that the president is correct and
> 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. What
> The population proportion is .30. What is the probability that a sample proportion will be within ±.04 of the population proportion for each of the following sample sizes? a. n = 100 b. n = 200 c. n = 500 d. n = 1000 e. What is the advantage of a larger
> A population proportion is .40. A sample of size 200 will be taken and the sample proportion / will be used to estimate the population proportion. a. What is the probability that the sample proportion will be within ±.03 of the population proportion? b.
> To estimate the mean age for a population of 4000 employees, a simple random sample of 40 employees is selected. a. Would you use the finite population correction factor in calculating the standard error of the mean? Explain. b. If the population standar
> The CPA Practice Advisor reports that the mean preparation fee for 2017 federal income tax returns was $273. Use this price as the population mean and assume the population standard deviation of preparation fees is $100. a. What is the probability that t
> The state of California has a mean annual rainfall of 22 inches, whereas the state of New York has a mean annual rainfall of 42 inches. Assume that the standard deviation for both states is 4 inches. A sample of 30 years of rainfall for California and a
> The Economic Policy Institute periodically issues reports on worker’s wages. The institute reported that mean wages for male college graduates were $37.39 per hour and for female college graduates were $27.83 per hour in 2017. Assume the standard deviati
> In May 2018, The College Board reported the following mean scores for two parts of the Scholastic Aptitude Test (SAT): Evidence-Based Reading and Writing………….533 Mathematics……………………………………………….527 Assume that the population standard deviation on each part
> Barron’s reported that the average number of weeks an individual is unemployed is 17.5 weeks. Assume that for the population of all unemployed individuals the population mean length of unemployment is 17.5 weeks and that the population standard deviation
> In the EAI sampling problem (see Figure 7.5), we showed that for n = 30, there was .5034 probability of obtaining a sample mean within ±$500 of the population mean. a. What is the probability that is within $500 of the population mean if
> CBSSports.com developed the Total Player Ratings system to rate players in the National Basketball Association (NBA) based upon various offensive and defensive statistics. The following data show the average number of points scored per game (PPG) for 50
> Sampling Distribution for Electronic Associates, Inc., Managers. Refer to the EAI sampling problem. Suppose a simple random sample of 60 managers is used. a. Sketch the sampling distribution of / when simple random samples of size 60 are used. b. What ha
> Suppose a random sample of size 50 is selected from a population with s = 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
> 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 x is used to estimate m. a. What is the probability that the sample mean will be within ±5 of the population mean? b. What is the probability that
> 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 will be used to estimate the population mean. a. What is the expected value of ? b. What is the standard deviation of ? c. Show the s
> 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
> 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
> A random variable is normally distributed with a mean of m = 50 and a standard deviation of s = 5. a. Sketch a normal curve for the probability density function. Label the horizontal axis with values of 35, 40, 45, 50, 55, 60, and 65. Figure 6.6 shows th
> 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
> A Gallup Daily Tracking Survey found that the mean daily discretionary spending by Americans earning over $90,000 per year was $136 per day. The discretionary spending excluded home purchases, vehicle purchases, and regular monthly bills. Let x 5 the dis
> A doctor’s office staff studied the waiting times for patients who arrive at the office with a request for emergency service. The following data with waiting times in minutes were collected over a one-month period. Use classes of 0&acir
> 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
> Intensive care units (ICUs) generally treat the sickest patients in a hospital. ICUs are often the most expensive department in a hospital because of the specialized equipment and extensive training required to be an ICU doctor or nurse. Therefore, it is
> 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
> The time between arrivals of vehicles at a particular intersection follows an exponential probability distribution with a mean of 12 seconds. a. Sketch this exponential probability distribution. b. What is the probability that the arrival time between ve
> 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. 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 â
> Consider the following exponential probability density function. 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,
> 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
> OutdoorGearLab is an organization that tests outdoor gear used for climbing, camping, mountaineering, and backpacking. Suppose that the following data show the ratings of hardshell jackets based on the breathability, durability, versatility, features, mo
> 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
> Although studies continue to show smoking leads to significant health problems, 20% of adults in the United States smoke. Consider a group of 250 adults, and use the normal approximation of the binomial distribution to answer the questions below. a. What
> Assume a binomial probability distribution has p = .60 and n = 200. a. What are the mean and standard deviation? b. Is this situation one in which binomial probabilities can be approximated by the normal probability distribution? Explain. c. What is the
> A binomial probability distribution has p = .20 and n = 100. a. What are the mean and standard deviation? b. Is this situation one in which binomial probabilities can be approximated by the normal probability distribution? Explain. c. What is the probabi
> According to Money magazine, Maryland had the highest median annual household income of any state in 2018 at $75,847 (Time.com website). Assume that annual household income in Maryland follows a normal distribution with a median of $75,847 and standard d
> The time needed to complete a final examination in a particular college course is normally distributed with a mean of 80 minutes and a standard deviation of 10 minutes. Answer the following questions. a. What is the probability of completing the exam in
> Suppose that the mean daily viewing time of television is 8.35 hours. Use a normal probability distribution with a standard deviation of 2.5 hours to answer the following questions about daily television viewing per household. a. What is the probability
> Suppose that the average price for a gallon of gasoline in the United States is $3.73 and in Russia is $3.40. Assume these averages are the population means in the two countries and that the probability distributions are normally distributed with a stand
> Automobile repair costs continue to rise with an average 2015 cost of $367 per repair (U.S. News & World Report website). Assume that the cost for an automobile repair is normally distributed with a standard deviation of $88. Answer the following questio
> Martinez Auto Supplies has retail stores located in eight cities in California. The price they charge for a particular product in each city varies because of differing competitive conditions. For instance, the price they charge for a case of a popular br
> The average return for large-cap domestic stock funds over the three years was 14.4%. Assume the three-year returns were normally distributed across funds with a standard deviation of 4.4%. a. What is the probability an individual large-cap domestic stoc
> Males in the Netherlands are the tallest, on average, in the world with an average height of 183 centimeters (cm) (BBC News website). Assume that the height of men in the Netherlands is normally distributed with a mean of 183 cm and standard deviation of
> Given that z is a standard normal random variable, find z for each situation. a. The area to the right of z is .01. b. The area to the right of z is .025. c. The area to the right of z is .05. d. The area to the right of z is .10.
> Given that z is a standard normal random variable, find z for each situation. a. The area to the left of z is .2119. b. The area between −z and z is .9030. c. The area between −z and z is .2052. d. The area to the left of z is .9948. e. The area to the r
> Given that z is a standard normal random variable, find z for each situation. a. The area to the left of z is .9750. b. The area between 0 and z is .4750. c. The area to the left of z is .7291. d. The area to the right of z is .1314. e. The area to the l
> Given that z is a standard normal random variable, compute the following probabilities. a. P(−1.98 ≤ z ≤ .49) b. P(.52 ≤ z ≤ 1.22) c. P(−1.75 ≤ z ≤ −1.04)
> Given that z is a standard normal random variable, compute the following probabilities. a. P(0 ≤ z ≤ .83) b. P(−1.57 ≤ z ≤ 0) c. P(z > .44) d. P(z ≥ −.23) e. P(z < 1.20) f. P(z ≤ −.71)
> Given that z is a standard normal random variable, compute the following probabilities. a. P(z ≤ −1.0) b. P(z ≥ −1) c. P(z ≥ −1.5) d. P(−2.5 ≤ z) e. P(−3 < z ≤ 0)
> The probability distribution for the random variable x follows. a. Is this probability distribution valid? Explain. b. What is the probability that x = 30? c. What is the probability that x is less than or equal to 25? d. What is the probability that x
> The Troubled Asset Relief Program (TARP), passed by the U.S. Congress in October 2008, provided $700 billion in assistance for the struggling U.S. economy. Over $200 billion was given to troubled financial institutions with the hope that there would be a
> The following data show the number of rental cars in service (in thousands) for three rental car companies: Hertz, Avis, and Dollar over a three-year period (Auto Rental News website). a. Construct a time series graph for the years 2007 to 2010 showing
> Axline Computers manufactures personal computers at two plants, one in Texas and the other in Hawaii. The Texas plant has 40 employees; the Hawaii plant has 20. A random sample of 10 employees is to be asked to fill out a benefits questionnaire. a. What
> Blackjack, or twenty-one as it is frequently called, is a popular gambling game played in casinos. A player is dealt two cards. Face cards (jacks, queens, and kings) and tens have a point value of 10. Aces have a point value of 1 or 11. A 52-card deck co
> Suppose N = 10 and r = 3. Compute the hypergeometric probabilities for the following values of n and x. a. n = 4, x = 1. b. n = 2, x = 2. c. n = 2, x = 0. d. n = 4, x = 2. e. n = 4, x = 4.
> Airline passengers arrive randomly and independently at the passenger-screening facility at a major international airport. The mean arrival rate is 10 passengers per minute. a. Compute the probability of no arrivals in a one-minute period. b. Compute the
> In a one-year period, New York City had a total of 11,232 motor vehicle accidents that occurred on Monday through Friday between the hours of 3 p.m. and 6 p.m. (New York State Department of Motor Vehicles website). This corresponds to mean of 14.4 accide
