If n = 200 and X = 50, construct a 95% confidence interval estimate for the population proportion.
> If you use a 0.10 level of significance in a two-tail hypothesis test, what is your decision rule for rejecting a null hypothesis that the population mean equals 500 if you use the Z test?
> If you use a 0.05 level of significance in a two-tail hypothesis test, what decision will you make if ZSTAT = +2.21?
> If you use a 0.05 level of significance in a two-tail hypothesis test, what decision will you make if ZSTAT = -0.76?
> Consider the confidence interval estimate discussed in Problem 8.5. Suppose the population mean time spent on the site is 36 minutes a day. Is the confidence interval estimate stated in Problem 8.5 correct? Explain.
> A survey of nonprofit organizations showed that online fundraising has increased in the past year. Based on a random sample of 133 nonprofits, the mean one-time gift donation resulting from email outreach in the past year was $87. Assume that the sample
> Referring to the results in Problem 8.66 concerning the answer time of calls, write a report that summarizes your conclusions.
> The manufacturer of Boston and Vermont asphalt shingles knows that product weight is a major factor in a customer’s perception of quality. The last stage of the assembly line packages the shingles before they are placed on wooden pallets. Once a pallet i
> The manufacturer of Boston and Vermont asphalt shingles knows that product weight is a major factor in a customer’s perception of quality. The last stage of the assembly line packages the shingles before they are placed on wooden pallets. Once a pallet i
> Call centers today play an important role in managing day-today business communications with customers. It’s important, therefore, to monitor a comprehensive set of metrics, which can help businesses understand the overall performance of a call center. O
> A quality characteristic of interest for a tea-bag-filling process is the weight of the tea in the individual bags. In this example, the label weight on the package indicates that the mean amount is 5.5 grams of tea in a bag. If the bags are underfilled,
> Claims fraud (illegitimate claims) and buildup (exaggerated loss amounts) continue to be major issues of concern among automobile insurance companies. Fraud is defined as specific material misrepresentation of the facts of a loss; buildup is defined as t
> The manufacturer of Ice Melt claims that its product will melt snow and ice at temperatures as low as 0° Fahrenheit. A representative for a large chain of hardware stores is interested in testing this claim. The chain purchases a large shipment of 5-poun
> You are the manager of a restaurant that delivers pizza to college dormitory rooms. You have just changed your delivery process in an effort to reduce the mean time between the order and completion of delivery from the current 25 minutes. A sample of 36
> Suppose that you are going to collect a set of data, either from an entire population or from a random sample taken from that population. a. Which statistical measure would you compute first: the mean or the standard deviation? Explain. b. What does your
> How do smartphone owners use their smartphones when shopping in a grocery store? A sample of 731 smartphone owners in the United States revealed that 358 use their smartphone to access digital coupons, 355 look up recipes, 234 read reviews of products an
> A GlobalWebIndex study noted the percentage of Internet users that owned various devices. Suppose that a survey of 1,000 Internet users found that 840 own a PC/laptop, 910 own a smartphone, 500 own a tablet, and 100 own a smart watch. Source: Data extrac
> Why is the sample size needed to determine the proportion smaller when the population proportion is 0.20 than when the population proportion is 0.50?
> Why is it true that for a given sample size, n, an increase in confidence is achieved by widening (and making less precise) the confidence interval?
> When should you use the t distribution to develop the confidence interval estimate for the mean?
> Patient waiting is a common phenomenon in the doctor’s waiting room. One acceptable standard of practice states that waiting time for patients to be seen by the first provider in hospital outpatient and public health clinics should be less than 30 minute
> Why can you never really have 100% confidence of correctly estimating the population characteristic of interest?
> A market researcher selects a simple random sample of n = 100 Twitter users from a population of over 100 million Twitter registered users. After analyzing the sample, she states that she has 95% confidence that the mean time spent on the site per day is
> Personal data is the new currency of the digital economy. How do consumers feel about sharing personal data with their communication service providers (CSPs)? A recent IBM report highlights that 40% of 18- to 25-year-old consumers are comfortable sharing
> Cybersecurity is a critical business issue that demands the attention of business and IT executives. According to a study released by PwC, 38% of surveyed business and IT executives reported phishing scams at their institutions. Source: Data extracted f
> In a study of 443 nonprofits nationwide, 130 indicated that the greatest diversity staffing challenge they face is retaining younger staff (those under 30). Source: Data extracted from “2016 Nonprofit Employment Practices Survey,” Nonprofit HR, 2016, bi
> A Federal Reserve Bank of Atlanta report looks at what strategies and measures financial institutions are pursuing to provide mobile financial services to their customers. In response to a survey question about barriers hindering greater consumer adoptio
> What does brand loyalty mean to consumers? According to a Rare research report, 20% of consumers associate trust with brand loyalty. Source: Data extracted from “Redefining Loyalty,” Rare, 2016, bit.ly/2solA40. a. To conduct a follow-up study that would
> A growing niche in the restaurant business is gourmet-casual breakfast, lunch, and brunch. Chains in this group include Panera Bread. Suppose that the mean per-person check for breakfast at Panera Bread is approximately $9.50. a. Assuming a standard devi
> An advertising media analyst wants to estimate the mean amount of time that consumers spend with digital media daily. From past studies, the standard deviation is estimated as 45 minutes. a. What sample size is needed if the media analyst wants to be 90%
> An advertising media analyst wants to estimate the mean weekly amount of time consumers spend watching television daily. Based on previous studies, the standard deviation is assumed to be 20 minutes. The media analyst wants to estimate, with 99% confiden
> CarMD reports that after two years of flat U.S. car repair costs, 2016 saw an increase. One of the most common problems that trigger the “check engine” light is the catalytic converter. Repairing the catalytic converter had a mean repair cost of $1,190 i
> If the inspection division of a county weights and measures department wants to estimate the mean amount of soft-drink fill in 2-liter bottles to within ±0.01 liter with 95% confidence and also assumes that the standard deviation is 0.05 liter, what samp
> If a light bulb manufacturing company wants to estimate, with 95% confidence, the mean life of light emitting diode (LED) light bulbs to within ±400 hours and also assumes that the population standard deviation is 1,500 hours, how many LED light bulbs ne
> Is it true in Example 8.1 on page 280 that you do not know for sure whether the population mean is between 366.33 and 372.21 grams? Explain.
> If the manager of a bottled water distributor wants to estimate, with 95% confidence, the mean amount of water in a 1-gallon bottle to within ±0.004 gallon and also assumes that the standard deviation is 0.02 gallon, what sample size is needed?
> A survey is planned to determine the mean annual family medical expenses of employees of a large company. The management of the company wishes to be 95% confident that the sample mean is correct to within ±$50 of the population mean annual family medical
> If you want to be 95% confident of estimating the population proportion to within a sampling error of ±0.02 and there is historical evidence that the population proportion is approximately 0.40, what sample size is needed?
> If you want to be 99% confident of estimating the population proportion to within a sampling error of ±0.04, what sample size is needed?
> If you want to be 99% confident of estimating the population mean to within a sampling error of ±20 and the standard deviation is assumed to be 100, what sample size is required?
> If you want to be 95% confident of estimating the population mean to within a sampling error of ±5 and the standard deviation is assumed to be 15, what sample size is required?
> What business, economic, policy, and environmental threats to organization growth are CEOs extremely concerned about? In a survey by PricewaterhouseCoopers (PwC), 57 of 114 U.S. CEOs are extremely concerned about cyber threats, and 22 are extremely conce
> The Washington Metropolitan Area Transit Authority has set a bus fleet reliability goal of 8,000 bus miles. Bus reliability is measured specifically as the number of bus miles traveled before a mechanical breakdown that requires the bus to be removed fro
> A Pew Research Center survey of 4,787 adults found that 4,178 had bought something online. Of these online shoppers, 789 are weekly online shoppers. a. Construct a 95% confidence interval estimate of the population proportion of adults who had bought so
> In a survey of 823 human resource professionals concerning challenges they faced in the workplace, 329 said that employee retention/turnover was an important challenge and 181 said that employee satisfaction was an important challenge. Source: Data extra
> What do you value most when shopping in a retail store? According to a TimeTrade survey, 26% of consumers value personalized experience most. Source: Data extracted from “The State of Retail, 2017,” TimeTrade, bit.ly/2rFGf7o. a. Suppose that the survey h
> Why is it not possible in Example 8.1 on page 280 to have 100% confidence? Explain.
> In a survey of 1,003 adults concerning complaints about restaurants, 732 complained about dirty or ill-equipped bathrooms and 381 complained about loud or distracting diners at other tables. Source: Data extracted from “The Gripe-O-Meter Restaurants,” Co
> A cellphone provider has the business objective of wanting to estimate the proportion of subscribers who would upgrade to a new cellphone with improved features if it were made available at a substantially reduced cost. Data are collected from a random s
> If n = 400 and X = 25, construct a 99% confidence interval estimate for the population proportion.
> One operation of a mill is to cut pieces of steel into parts that are used in the frame for front seats in an automobile. The steel is cut with a diamond saw, and the resulting parts must be cut to be within {0.005 inch of the length specified by the aut
> The file MobileCommerce contains mobile commerce penetration values (the percentage of the country population that bought something online via a mobile phone in the past month) for twenty-eight of the world’s economies: 23 27 26 25 40 19 26 36 23 33 23
> In Problem 9.44, what is your statistical decision if tSTAT = -1.15? Problem 9.44: In a one-tail hypothesis test where you reject H0 only in the lower tail, what is the critical value of the tSTAT test statistic with 20 degrees of freedom at the 0.01 le
> A manufacturing company produces electric insulators. You define the variable of interest as the strength of the insulators. If the insulators break when in use, a short circuit is likely. To test the strength of the insulators, you carry out destructive
> One of the major measures of the quality of service provided by any organization is the speed with which the organization responds to customer complaints. A large family-held department store selling furniture and flooring, including carpet, had undergon
> The manufacturer of Boston and Vermont asphalt shingles provides its customers with a 20-year warranty on most of its products. To determine whether a shingle will last through the warranty period, accelerated-life testing is conducted at the manufacturi
> Studies conducted by the manufacturer of Boston and Vermont asphalt shingles have shown product weight to be a major factor in the customer’s perception of quality. Moreover, the weight represents the amount of raw materials being used and is therefore v
> An important quality characteristic used by the manufacturer of Boston and Vermont asphalt shingles is the amount of moisture the shingles contain when they are packaged. Customers may feel that they have purchased a product lacking in quality if they fi
> Call centers today play an important role in managing dayto- day business communications with customers. It’s important, therefore, to monitor a comprehensive set of metrics, which can help businesses understand the overall performance of a call center.
> A bank branch located in a commercial district of a city has the business objective of improving the process for serving customers during the noon-to-1:00 p.m. lunch period. The waiting time (defined as the time the customer enters the line until he or s
> An auditor for a government agency was assigned the task of evaluating reimbursement for office visits to physicians paid by Medicare. The audit was conducted on a sample of 75 reimbursements, with the following results: • In 12 of the office visits, the
> The owner of a specialty coffee shop wants to study coffee purchasing habits of customers at her shop. She selects a random sample of 60 customers during a certain week, with the following results: • The amount spent was X = $7.25, S = $1.75. • Thirty-on
> IAB conducted a study of 821 U.S. adults to understand the behavioral shift of consumers’ TV viewing experience. The study found that 460 of U.S. adults own streaming enabled TVs, including smart TVs and video streaming devices. Source: The Changing TV E
> In a one-tail hypothesis test where you reject H0 only in the lower tail, what is the critical value of the tSTAT test statistic with 20 degrees of freedom at the 0.01 level of significance?
> Is there a difference in the yields of different types of investments? The file CDRate contains the yields for a one-year certificate of deposit (CD) and a five-year CD for 39 banks listed for West Palm Beach, Florida on January 9, 2017. Source: Data ext
> Referring to the results of Problems 10.67 and 10.68 concerning the weight and granule loss of Boston and Vermont shingles, write a report that summarizes your conclusions.
> Market data indicates that smartphone users are very concerned about the battery life of their smartphones. An experiment is conducted in which the battery life of a newly designed smartphone battery is compared to the battery life of an existing smartph
> The manufacturer of Boston and Vermont asphalt shingles provides its customers with a 20-year warranty on most of its products. To determine whether a shingle will last as long as the warranty period, the manufacturer conducts accelerated- life testing.
> The manufacturer of Boston and Vermont asphalt shingles knows that product weight is a major factor in the customer’s perception of quality. Moreover, the weight represents the amount of raw materials being used and is therefore very important to the com
> The owner of a restaurant that serves Continental-style entrées has the business objective of learning more about the patterns of patron demand during the Friday-to-Sunday weekend time period. She decided to study the demand for dessert duri
> A hotel manager looks to enhance the initial impressions that hotel guests have when they check in. Contributing to initial impressions is the time it takes to deliver a guest’s luggage to the room after check-in. A random sample of 20 deliveries on a pa
> The lengths of life (in hours) of a sample of 40 6-watt light emitting diode (LED) light bulbs produced by manufacturer A and a sample of 40 6-watt light emitting diode (LED) light bulbs produced by manufacturer B are stored in Bulbs . Completely analyze
> Do social shoppers differ from other online consumers with respect to spending behavior? A study of browser-based shopping sessions reported that social shoppers, consumers who click away from social networks to retail sites or share an item on a social
> A computer information systems professor is interested in studying the amount of time it takes students enrolled in the Introduction to Computers course to write a program in VB.NET. The professor hires you to analyze the following results (in minutes),
> In Problem 9.42, what is your statistical decision if tSTAT = +2.39?
> The file Restaurants contains the ratings for food, décor, service, and the price per person for a sample of 50 restaurants located in a center city and 50 restaurants located in an outlying area. Completely analyze the differences between center city an
> The annual NFL Super Bowl is the most widely watched sporting event in the United States each year. In recent years, there has been a great deal of interest in the ads that appear during the game. These ads vary in length with most lasting 30 seconds or
> Do males and females differ in the amount of time they spend online and the amount of time they spend playing games while online? A study reported that women spent a mean of 1,254 minutes per week online as compared to 1,344 minutes per week for men. Sup
> How do private universities and public colleges compare with respect to debt at graduation incurred by students? The file CollegeDebt contains the average debt at graduation incurred by students for 100 private universities and 100 public colleges, as re
> The American Society for Quality (ASQ) conducted a salary survey of all its members. ASQ members work in all areas of manufacturing and service-related institutions, with a common theme of an interest in quality. Two job titles are black belt and green b
> Under what conditions should you use the paired t test for the mean difference between two related populations?
> When you have two independent populations, explain the similarities and differences between the test of hypothesis for the difference between the means and the confidence interval estimate for the difference between the means.
> What is the distinction between repeated measurements and matched items?
> What is the distinction between two independent populations and two related populations?
> In a one-tail hypothesis test where you reject H0 only in the upper tail, what is the critical value of the t-test statistic with 10 degrees of freedom at the 0.01 level of significance?
> In Problem 3.69 on page 156, you were introduced to a teabag-filling operation. An important quality characteristic of interest for this process is the weight of the tea in the individual bags. The file Teabags contains an ordered array of the weight, in
> A manufacturing company produces steel housings for electrical equipment. The main component part of the housing is a steel trough that is made out of a 14-gauge steel coil. It is produced using a 250-ton progressive punch press with a wipe-down operatio
> One of the major measures of the quality of service provided by any organization is the speed with which it responds to customer complaints. A large family-held department store selling furniture and flooring, including carpet, had undergone a Major expa
> The operations manager at a light emitting diode (LED) light bulb factory needs to estimate the mean life of a large shipment of LEDs. The manufacturer’s specifications are that the standard deviation is 1,500 hours. A random sample of 64 LEDs indicated
> One theory concerning the Dow Jones Industrial Average is that it is likely to increase during U.S. presidential election years. From 1964 through 2016, the Dow Jones Industrial Average increased in 11 of the 14 U.S. presidential election years. Assuming
> Three coins are tossed. a. Give an example of a simple event. b. Give an example of a joint event. c. What is the complement of a head on the first toss? d. What does the sample space consist of?
> Smartphone adoption among American younger adults has increased substantially and mobile access to the Internet is pervasive. Seventeen percent of young adults, ages 18–29, who own a smartphone are “smartphone-dependent,” meaning that they do not have ho
> Between 1896—when the Dow Jones index was created— and 2016, the index rose in 67% of the years. Sources: M. Hulbert, “What the Past Can’t Tell Investors,” The New York Times, January 3, 2010, p. BU2 and bit.ly/100zwvT. Based on this information, and as
> Darwin Head, a 35-year-old sawmill worker, won $1 million and a Chevrolet Malibu Hybrid by scoring 15 goals within 24 seconds at the Vancouver Canucks National Hockey League game (B. Ziemer, “Darwin Evolves into an Instant Millionaire,” Vancouver Sun, Fe
> What are the four properties that must be present in order to use the Poisson distribution?
> Webrooming, researching products online before buying them in store, has become the new norm for some consumers and contrasts with showrooming, researching products in a physical store before purchasing online. A recent study by Interactions reported tha
> What are the four properties that must be present in order to use the binomial distribution?
> What is the meaning of the expected value of a variable?
> 5.29 A toll-free phone number is available from 9 a.m. to 9 p.m. for your customers to register complaints about a product purchased from your company. Past history indicates that a mean of 0.8 calls is received per minute. a. What properties must be tr
> One of the major measures of the quality of service provided by an organization is the speed with which the organization responds to customer complaints. A large family-held department store selling furniture and flooring, including carpet, had undergone
> As player salaries have increased, the cost of attending basketball games has increased dramatically. The file NBACost contains the cost of four tickets purchased on the secondary market, two beers, two soft drinks, four hot dogs, and one parking space a
