Question: The manager of a computer software company
The manager of a computer software company wishes to study the number of hours per week senior executives by type of industry spend at their desktop computers. The manager selected a sample of five executives from each of three industries. At the .05 significance level, can she conclude there is a difference in the mean number of hours spent per week by industry?
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> Assume a binomial distribution where n = 5 and π = .30. a. Refer to Appendix B.1 and list the probabilities for values of x from 0 to 5. b. Determine the mean and standard deviation of the distribution from the general definitions given in formulas (6–1)
> Aloha Banking Co. is studying ATM use in suburban Honolulu. Yesterday, for a sample of 30 ATM's, the bank counted the number of times each machine was used. The data is presented in the table. Develop a stem-and-leaf chart to summarize the data. What wer
> The box plot shows the undergraduate in-state tuition per credit hour at four-year public colleges. a. Estimate the median. b. Estimate the first and third quartiles. c. Determine the interquartile range. d. Beyond what point is a value considered an o
> A firm will promote two employees out of a group of six men and three women. a. List all possible outcomes. b. What probability concept would be used to assign probabilities to the outcomes?
> A small business consultant is investigating the performance of several companies. The fourth-quarter sales for last year (in thousands of dollars) for the selected companies were: Company ____________Fourth-Quarter Sales ($ thousands) Hoden Building Pr
> The following is a list of 29 hospitals in the Cincinnati, Ohio, and Northern Kentucky region. Each hospital is assigned a number, 00 through 28. The hospitals are classified by type, either a general medical/surgical hospital (M/S) or a specialty hospit
> A quality control inspector selects a part to be tested. The part is then declared acceptable, repairable, or scrapped. Then another part is tested. List the possible outcomes of this experiment regarding two parts.
> A mail-order company counted the number of incoming calls per day to the company’s toll-free number during the first 7 days in May: 14, 24, 19, 31, 36, 26, 17. (a) Compute the arithmetic mean and (b) Indicate whether it is a statistic or a parameter.
> A recent article suggested that, if you earn $25,000 a year today and the inflation rate continues at 3% per year, you’ll need to make $33,598 in 10 years to have the same buying power. You would need to make $44,771 if the inflation rate jumped to 6%. C
> The American Diabetes Association recommends a blood glucose reading of less than 130 for those with Type 2 diabetes. Blood glucose measures the amount of sugar in the blood. Below are the readings for February for a person recently diagnosed with Type 2
> Rolland Poust is a sophomore in the College of Business at Scandia Tech. Last semester he took courses in statistics and accounting, 3 hours each, and earned an A in both. He earned a B in a 5-hour history course and a B in a 2-hour history of jazz cours
> 54. The mean income of a group of sample observations is $500; the standard deviation is $40. According to Chebyshev’s theorem, at least what percent of the incomes will lie between $400 and $600?
> A consumer watchdog organization is concerned about credit card debt. A survey of 10 young adults with credit card debt of more than $2,000 showed they paid an average of just over $100 per month against their balances. Listed below are the amounts each
> A recent article in the Cincinnati Enquirer reported that the mean labor cost to repair a heat pump is $90 with a standard deviation of $22. Monte’s Plumbing and Heating Service completed repairs on two heat pumps this morning. The labor cost for the fir
> The sample of eight companies in the aerospace industry, referred to in Exercise 38, was surveyed as to their return on investment last year. The results are 10.6, 12.6, 14.8, 18.2, 12.0, 14.8, 12.2, and 15.6. a. Compute the sample variance. b. Determine
> The following five values are a sample: 11, 6, 10, 6, and 7. a. Compute the sample variance. b. Determine the sample standard deviation.
> Referring to Exercise 43, the annual report of Dennis Industries also gave these returns on stockholder equity for the same 5-year period (in percent): 13.2, 5.0, 10.2, 17.5, and 12.9. a. What is the arithmetic mean return? b. What is the variance? In E
> Consider these six values a population: 13, 3, 8, 10, 8, and 6. a. Determine the mean of the population. b. Determine the variance.
> a. Compute the mean of the following sample values: 1.3, 7.0, 3.6, 4.1, 5. 0. b. Show that Σ(x − x̅) = 0
> Compute the geometric mean of the following weekly percent increases: 2, 8, 6, 4, 10, 6, 8, and 4.
> Andrews and Associates specialize in corporate law. They charge $100 an hour for researching a case, $75 an hour for consultations, and $200 an hour for writing a brief. Last week one of the associates spent 10 hours consulting with her client, 10 hours
> The demand for the video games provided by Mid-Tech Video Games Inc. has exploded in the last several years. Hence, the owner needs to hire several new technical people to keep up with the demand. Mid-Tech gives each applicant a special test that Dr. McG
> Sally Reynolds sells real estate along the coastal area of Northern California. Below are her total annual commissions between 2005 and 2015. Find the mean, median, and mode of the commissions she earned for the 11 years. Year ______Amount (thousands) 2
> The following hypotheses are given. H0: ρ ≥ 0 H1: ρ < 0 A random sample of 15 paired observations has a correlation of −.46. Can we conclude that the correlation in the population is less than zero? Use the .05 significance level.
> Kevin Horn is the national sales manager for National Textbooks Inc. He has a sales staff of 40 who visit college professors all over the United States. Each Saturday morning he requires his sales staff to send him a report. This report includes, among o
> The following regression equation was computed from a sample of 20 observations: ŷ = 15 − 5x SSE was found to be 100 and SS total, 400. a. Determine the standard error of estimate. b. Determine the coefficient of determination. c. Determine the correlati
> For a sample of 40 large U.S. cities, the correlation between the mean number of square feet per office worker and the mean monthly rental rate in the central business district is −0.363. At the .05 significance level, can we conclude that there is a neg
> A sociologist claims that the success of students in college (measured by their GPA) is related to their family’s income. For a sample of 20 students, the correlation coefficient is 0.40. Using the 0.01 significance level, can we conclude that there is a
> Refer to Exercise 16. In Exercise 16 Mr. James McWhinney, president of Daniel-James Financial Services, believes there is a relationship between the number of client contacts and the dollar amount of sales. To document this assertion, Mr. McWhinney gath
> Refer to Exercise 14. In Exercise 14 The following sample of observations was randomly selected. a. Determine the .95 confidence interval for the mean predicted when x = 7. b. Determine the .95 prediction interval for an individual predicted when x =
> On the first statistics exam, the coefficient of determination between the hours studied and the grade earned was 80%. The standard error of estimate was 10. There were 20 students in the class. Develop an ANOVA table for the regression analysis of hours
> Refer to Exercise 16. Determine the standard error of estimate and the coefficient of determination. Interpret the coefficient of determination. In Exercise 16 Mr. James McWhinney, president of Daniel-James Financial Services, believes there is a relati
> Refer to Exercise 6. Determine the standard error of estimate and the coefficient of determination. Interpret the coefficient of determination. In Exercise 6 The owner of Maumee Ford-Volvo wants to study the relationship between the age of a car and its
> Refer to Exercise 18. The regression equation is ŷ = 9.9198 − 0.00039x, the sample size is 9, and the standard error of the slope is 0.0032. Use the .05 significance level. Can we conclude that the slope of the regression
> Refer to Exercise 6. The regression equation is ŷ = 11.18 − 0.49x, the sample size is 12, and the standard error of the slope is 0.23. Use the .05 significance level. Can we conclude that the slope of the regression line i
> The Downtown Parking Authority of Tampa, Florida, reported the following information for a sample of 250 customers on the number of hours cars are parked and the amount they are charged. a. Convert the information on the number of hours parked to a pro
> Refer to Exercise 6. In Exercise 6 The owner of Maumee Ford-Volvo wants to study the relationship between the age of a car and its selling price. Listed below is a random sample of 12 used cars sold at the dealership during the last year. a. Determine
> A study of 20 worldwide financial institutions showed the correlation between their assets and pretax profit to be .86. At the .05 significance level, can we conclude that there is positive correlation in the population?
> A stockbroker at Critical Securities reported that the mean rate of return on a sample of 10 oil stocks was 12.6% with a standard deviation of 3.9%. The mean rate of return on a sample of 8 utility stocks was 10.9% with a standard deviation of 3.5%. At t
> The following hypotheses are given. H0: σ21 ≤ σ22 H1: σ21 > σ22 A random sample of five observations from the first population resulted in a standard deviation of 12. A random sample of seven observations from the second population showed a standard devi
> There are four auto body shops in Bangor, Maine, and all claim to promptly repair cars. To check if there is any difference in repair times, customers are randomly selected from each repair shop and their repair times in days are recorded. The output fro
> The amount of income spent on housing is an important component of the cost of living. The total costs of housing for homeowners might include mortgage payments, property taxes, and utility costs (water, heat, electricity). An economist selected a sample
> The following data on annual rates of return were collected from eleven randomly selected stocks listed on the New York Stock Exchange (“the big board”) and twelve randomly selected stocks listed on NASDAQ. Assume the population standard deviations are t
> A candy company taste-tested two chocolate bars, one with almonds and one without almonds. A panel of testers rated the bars on a scale of 0 to 5, with 5 indicating the highest taste rating. Assume the population standard deviations are equal. At the .05
> The president of the American Insurance Institute wants to compare the yearly costs of auto insurance offered by two leading companies. He selects a sample of 15 families, some with only a single insured driver, others with several teenage drivers, and p
> A number of minor automobile accidents occur at various high-risk intersections in Teton County despite traffic lights. The Traffic Department claims that a modification in the type of light will reduce these accidents. The county commissioners have agre
> Determine the median and the first and third quartiles in the following data. 5.24 6.02 6.67 7.30 7.59 7.99 8.03 8.35 8.81 9.45 9.61 10.37 10.39 11.86 12.22 12.71 13.07 13.59 13.89 15.42
> Compute the mean and variance of the following discrete probability distribution. x ________P(x) 2 …………………. .5 8 …………………. .3 10 …………….…. .2
> The following are six observations collected from treatment 1, ten observations collected from treatment 2, and eight observations collected from treatment 3. Test the hypothesis that the treatment means are equal at the .05 significance level. a. Stat
> The following are six observations collected from treatment 1, four observations collected from treatment 2, and five observations collected from treatment 3. Test the hypothesis at the .05 significance level that the treatment means are equal. a. Stat
> Refer to the Baseball 2016 data, which report information on the 30 Major League Baseball teams for the 2016 season. a. At the .05 significance level, can we conclude that there is a difference in the mean salary of teams in the American League versus te
> A goal of financial literacy for children is to learn how to manage money wisely. One question is: How much money do children have to manage? A recent study by Schnur Educational Research Associates randomly sampled 15 children between 8 and 10 years old
> Businesses such as General Mills, Kellogg’s, and Betty Crocker regularly use coupons to build brand allegiance and stimulate sales. Marketers believe that the users of paper coupons are different from the users of e-coupons accessed through the Internet.
> Refer to the Lincolnville school bus data. Set up a variable that divides the age of the buses into three groups: new (less than 5 years old), medium (5 but less than 10 years), and old (10 or more years). The median maintenance cost is $4,179. Based on
> A computer manufacturer offers technical support that is available 24 hours a day, 7 days a week. Timely resolution of these calls is important to the company’s image. For 35 calls that were related to software, technicians resolved the issues in a mean
> The distribution of the number of viewers for the American Idol television show follows a normal distribution with a mean of 29 million and a standard deviation of 5 million. What is the probability next week’s show will: a. Have between 30 and 34 millio
> Refer to the North Valley Real Estate data, which report information on homes sold during the last year. a. Sort the data into a table that shows the number of homes that have a pool versus the number that don’t have a pool in each of the five townships.
> Clark Heter is an industrial engineer at Lyons Products. He would like to determine whether there are more units produced on the night shift than on the day shift. The mean number of units produced by a sample of 54 day-shift workers was 345. The mean nu
> There are five sales associates at Mid-Motors Ford. The five associates and the number of cars they sold last week are: Sales Associate _________Cars Sold Peter Hankish ………………….………………. 8 Connie Stallter …………………………………. 6 Juan Lopez ……………………..………………. 4 Ted
> The federal government recently granted funds for a special program designed to reduce crime in high-crime areas. A study of the results of the program in eight high-crime areas of Miami, Florida, yielded the following results. Has there been a decreas
> The null and alternate hypotheses are: H0: μd = 0 H1: μd ≠0 The following paired observations show the number of traffic citations given for speeding by Officer Dhondt and Officer Meredith of the South Carol
> Refer to the Lincolnville School District bus data. Prepare a report on the maintenance cost for last month. Be sure to answer the following questions in your report. a. Around what values do the data tend to cluster? Specifically what was the mean maint
> Suppose you are an expert on the fashion industry and wish to gather information to compare the amount earned per month by models featuring Liz Claiborne attire with those of Calvin Klein. The following is the amount ($000) earned per month by a sample o
> Refer to the North Valley Real Estate data and prepare a report on the sales prices of the homes. Be sure to answer the following questions in your report. a. Around what values of price do the data tend to cluster? What is the mean sales price? What is
> The Tampa Bay (Florida) Area Chamber of Commerce wanted to know whether the mean weekly salary of nurses was larger than that of school teachers. To investigate, they collected the following information on the amounts earned last week by a sample of scho
> The following frequency distribution reports the electricity cost for a sample of 50 two-bedroom apartments in Albuquerque, New Mexico, during the month of May last year. Electricity Cost_____________Frequency $ 80 up to $100 ……………………………………….. 3 100 up
> In a marketing study, 100 consumers were asked to select the best digital music player from the iPod, the iRiver, and the Magic Star MP3. To summarize the consumer responses with a frequency table, how many classes would the frequency table have?
> A recent study compared the time spent together by single- and dual-earner couples. According to the records kept by the wives during the study, the mean amount of time spent together watching television among the single-earner couples was 61 minutes per
> The Kentucky Derby is held the first Saturday in May at Churchill Downs in Louisville, Kentucky. The race track is one and one-quarter miles. The following table shows the winners since 1990, their margin of victory, the winning time, and the payoff on a
> The null and alternate hypotheses are: H0: μ1 = μ2 H1: μ1 ≠ μ2 A random sample of 15 observations from the first population revealed a sample mean of 350 and a sample standard deviation of 12. A random sample of 17 observations from the second population
> A population consists of the following five values: 0, 0, 1, 3, 6. a. List all samples of size 3, and compute the mean of each sample. b. Compute the mean of the distribution of sample means and the population mean. Compare the two values. c. Compare the
> Creek Ratz is a very popular restaurant located along the coast of northern Florida. They serve a variety of steak and seafood dinners. During the summer beach season, they do not take reservations or accept “call aheadâ€
> Refer to the Baseball 2016 data, which report information on the 30 Major League Baseball teams for the 2016 season. Assume the 2016 data represents a sample. a. Develop a 95% confidence interval for the mean number of home runs per team. b. Develop a 95
> Health issues are a concern of managers, especially as they evaluate the cost of medical insurance. A recent survey of 150 executives at Elvers Industries, a large insurance and financial firm located in the Southwest, reported the number of pounds by wh
> Refer to the Lincolnville School District bus data. a. Refer to the maintenance cost variable. The mean maintenance cost for last year is $4,552 with a standard deviation of $2332. Estimate the number of buses with a maintenance cost of more than $6,000.
> The weights (in pounds) of a sample of five boxes being sent by UPS are 12, 6, 7, 3, and 10. a. Compute the range. b. Compute the standard deviation.
> Near the time of an election, a cable news service performs an opinion poll of 1,000 probable voters. It shows that the Republican contender has an advantage of 52% to 48%. a. Develop a 95% confidence interval for the proportion favoring the Republican c
> The state of Maryland has license plates with three numbers followed by three letters. How many different license plates are possible?
> Refer to the North Valley Real Estate data, which report information on homes sold during the last year. a. The mean selling price (in $ thousands) of the homes was computed earlier to be $357.0, with a standard deviation of $160.7. Use the normal distri
> Refer to the Lincolnville School District bus data. Information provided by manufacturers of school buses suggests the mean maintenance cost per year is $4,400 per bus with a standard deviation of $1,000. Compute the mean maintenance cost for the Lincoln
> Refer to the North Valley Real Estate data, which report information on the homes sold last year. Assume the 105 homes is a population. Compute the population mean and the standard deviation of price. Select a sample of 10 homes. Compute the mean. Determ
> Suppose we roll a fair die two times. a. How many different samples are there? b. List each of the possible samples and compute the mean. c. On a chart similar to Chart 8–2, compare the distribution of sample means with the distribution of the population
> For the following situations, would you collect information using a sample or a population? Why? a. Statistics 201 is a course taught at a university. Professor Rauch has taught nearly 1,500 students in the course over the past 5 years. You would like to
> The Appliance Center has six sales representatives at its North Jacksonville outlet. The following table lists the number of refrigerators sold by each representative last month. a. How many samples of size 2 are possible? b. Select all possible sample
> At the downtown office of First National Bank, there are five tellers. Last week, the tellers made the following number of errors each: 2, 3, 5, 3, and 5. a. How many different samples of two tellers are possible? b. List all possible samples of size 2 a
> Trudy Green works for the True-Green Lawn Company. Her job is to solicit lawncare business via the telephone. Listed below is the number of appointments she made in each of the last 25 hours of calling. What is the arithmetic mean number of appointments
> The price of shares of Bank of Florida at the end of trading each day for the last year followed the normal distribution. Assume there were 240 trading days in the year. The mean price was $42.00 per share and the standard deviation was $2.25 per share.
> According to the “January theory,” if the stock market is up for the month of January, it will be up for the year. If it is down in January, it will be down for the year. According to an article in The Wall Street Journal, this theory held for 29 out of
> Reynolds Construction Company has agreed not to erect all “look-alike” homes in a new subdivision. Five exterior designs are offered to potential home buyers. The builder has standardized three interior plans that can be incorporated in any of the five e
> Cruise ships of the Royal Viking line report that 80% of their rooms are occupied during September. For a cruise ship having 800 rooms, what is the probability that 665 or more are occupied in September?
> Recent difficult economic times have caused an increase in the foreclosure rate of home mortgages. Statistics from the Penn Bank and Trust Company show their monthly foreclosure rate is now 1 loan out of every 136 loans. Last month the bank approved 300
> Suppose 1.5% of the antennas on new Nokia cell phones are defective. For a random sample of 200 antennas, find the probability that: a. None of the antennas is defective. b. Three or more of the antennas are defective.
> Advertising expenses are a significant component of the cost of goods sold. Listed below is a frequency distribution showing the advertising expenditures for 60 manufacturing companies located in the Southwest. Estimate the mean and the standard deviatio
> Listed below is the population by state for the 15 states with the largest population. Also included is whether that state’s border touches the Gulf of Mexico, the Atlantic Ocean, or the Pacific Ocean (coastline). Note that 5 of the 1
> A population consists of the following five values: 2, 2, 4, 4, and 8. a. List all samples of size 2, and compute the mean of each sample. b. Compute the mean of the distribution of sample means and the population mean. Compare the two values. c. Compare
> SCCoast, an Internet provider in the Southeast, developed the following frequency distribution on the age of Internet users. Estimate the mean and the standard deviation. Age (years) ___________Frequency 10 up to 20………………………………… 3 20 up to 30 …………………………
> DJ LeMahieu of the Colorado Rockies had the highest batting average in the 2016 Major League Baseball season. His average was .348. So assume the probability of getting a hit is .348 for each time he batted. In a particular game, assume he batted three t
> Estimate the mean and the standard deviation of the following frequency distribution showing the number of times students eat at campus dining places in a month. Class ____________Frequency 0 up to 5 ……………………………….. 2 5 up to 10 ……………………………… 7 10 up to 1
> A recent news report indicated that 20% of all employees steal from their company each year. If a company employs 50 people, what is the probability that: a. Fewer than five employees steal? b. More than five employees steal? c. Exactly five employees st
> In establishing warranties on HDTVs, the manufacturer wants to set the limits so that few will need repair at the manufacturer’s expense. On the other hand, the warranty period must be long enough to make the purchase attractive to the buyer. For a new H
