(The data for this exercise are available at the text website: www.mhhe.com/Lind17e.) Refer to the Lincolnwood School District bus data. a. Suppose we consider a bus “old” if it has been in service more than 8 years. At the .01 significance level, can we conclude that less than 40% of the district’s buses are old? Report the p-value. b. Find the median maintenance cost and the median age of the buses. Organize the data into a two-by-two contingency table, with buses above and below the median of each variable. Determine whether the age of the bus is related to the amount of the maintenance cost. Use the .05 significance level. c. Is there a relationship between the maintenance cost and the manufacturer of the bus? Use the breakdown in part (b) for the buses above and below the median maintenance cost and the bus manufacturers to create a contingency table. Use the .05 significance level.
> Using the period 2000–02 as the base period, compute a simple index of international sales for each year from 2004 to 2015. Use the following information taken from Johnson & Johnson annual reports. The principal office of Johnson & John
> Using the period 2000–02 as the base period, compute a simple index of domestic sales for each year from 2004 to 2015. Use the following information taken from Johnson & Johnson annual reports. The principal office of Johnson & Johnson i
> The National Turkey Association wants to experiment with the effects of three different feed mixtures on weight gain in poults. Because no experience exists regarding the three mixtures, no assumptions regarding the population distribution of weights e
> For many years, TV executives used the guideline that 30% of the audience were watching each of the traditional big three prime-time networks and 10% were watching cable stations on a weekday night. A random sample of 500 viewers in the Tampa–St.
> The chief of security for the Mall of the Dakotas directed a study of theft. He selected a sample of 100 boxes that had been tampered with and ascertained that, for 60 of the boxes, the missing pants, shoes, and so on were attributed to shoplifting. Fo
> Refer to Table 10–4 and the example just completed. With n = 100, σ = 400, xÌ…c = 10,078, and μ1 = 10,100, verify that the probability of a Type II error is .2912. Table 10–4
> It has been suggested that daily production of a subassembly would be increased if better lighting were installed and background music and free coffee and doughnuts were provided during the day. Management agreed to try the scheme for a limited time. A
> The safety director of a large steel mill took samples at random from company records of minor work-related accidents and classified them according to the time the accident took place. Using the goodness-of-fit test and the .01 level of signif
> Grills Video Products purchases LCDs from Mira Electronics. According to his sampling plan, Art Grills, owner of Grills Video, will accept a shipment of LCDs if 3 or fewer are defective in a sample of 25. Develop an OC curve for these percents defectiv
> Classic Golf Inc. manages five courses in the Jacksonville, Florida, area. The director of golf wishes to study the number of rounds of golf played per weekday at the five courses. He gathered the following sample information. At the .05 significance l
> The liquid chlorine added to swimming pools to combat algae has a relatively short shelf life before it loses its effectiveness. Records indicate that the mean shelf life of a 5-gallon jug of chlorine is 2,160 hours (90 days). As an experiment, Holdlon
> The null hypothesis and the alternate hypothesis are: H0: The frequencies are equal. H1: The frequencies are not equal. Category ______fo A ………………………. 10 B ………&h
> Given the following hypotheses: H0: μ = 100 H1: μ ≠ 100 A random sample of six resulted in the following values: 118, 105, 112, 119, 105, and 111. Assume a normal population. Using the .05 significance level, can we conclude the mean is d
> In a multiple regression analysis, two independent variables are considered, and the sample size is 25. The regression coefficients and the standard errors are as follows. b1 = 2.676 sb1 = 0.56 b2 = −0.880 sb2 = 0.71 Conduct a test of hypo
> Most air travelers now use e-tickets. Electronic ticketing allows passengers to not worry about a paper ticket, and it costs the airline companies less to handle than paper ticketing. However, in recent times the airlines have received complaints from
> Johnson Wholesale Company manufactures a variety of products. The prices and quantities produced for April 2000 and April 2017 are: Using April 2000 as the base period, find the value index of goods produced for April 2017.
> The management of White Industries is considering a new method of assembling its golf cart. The present method requires a mean time of 42.3 minutes to assemble a cart. The mean assembly time for a random sample of 24 carts, using the new method, was 40
> Central Airlines claims that the median price of a round-trip ticket from Chicago to Jackson Hole, Wyoming, is $503. This claim is being challenged by the Association of Travel Agents, who believe the median price is less than $503. A random sample of
> Given the following hypotheses: H0: μ = 400 H1: μ ≠ 400 A random sample of 12 observations is selected from a normal population. The sample mean was 407 and the sample standard deviation 6. Using the .01 significance level: a. State the de
> The sales, in billions of dollars, of Keller Overhead Door Inc. for 2012 to 2017 are: a. Plot the data. b. Determine the least squares trend equation. c. Use the trend equation to calculate the points for 2014 and 2017. Plot them on the grap
> In January 2003, the price for a whole fresh chicken was $1.004 per pound. In February 2016, the price for the same chicken was $1.475 per pound. Use the January 2003 price as the base period and 100 as the base value to develop a simple index. By what
> The null and alternate hypotheses are: H0: π1 = π2 H1: π1 ≠ π2 A sample of 200 observations from the first population indicated that x1 is 170. A sample of 150 observations from the second population revealed x2 to be 110. Use the .05
> Many new stockbrokers resist giving presentations to bankers and certain other groups. Sensing this lack of self-confidence, management arranged to have a confidence-building seminar for a sample of new stockbrokers and enlisted Career Boosters for a t
> A sample of 60 college students was given a special training program designed to improve their time management skills. One month after completing the course, the students were contacted and asked whether the skills learned in the program were effective
> The following hypothesis-testing situation is given: H0: π = .50 and H1: π ≠ .50. The significance level is .05, and the sample size is 9. a. What is the decision rule? b. There were five successes. What is your decision regarding the null h
> The following hypotheses are given. H0: π = .40 H1: π ≠ .40 A sample of 120 observations revealed that p = .30. At the .05 significance level, can the null hypothesis be rejected? a. State the decision rule. b. Compute the value of the
> Thompson Photo Works purchased several new, highly sophisticated processing machines. The production department needed some guidance with respect to qualifications needed by an operator. Is age a factor? Is the length of service as an operator (in year
> A sample of 36 observations is selected from a normal population. The sample mean is 12, and the population standard deviation is 3. Conduct the following test of hypothesis using the .01 significance level. H0: μ ≤ 10 H1: μ > 10 (a) Is
> The numbers of “near misses” recorded for the last 20 months at Lima International Airport are 3, 2, 3, 2, 2, 3, 5, 1, 2, 2, 4, 4, 2, 6, 3, 5, 2, 5, 1, and 3. Develop an appropriate control chart. Determine the mean number of misses per mon
> Lahey Motors specializes in selling cars to buyers with a poor credit history. Listed below is the number of cars that were repossessed from Lahey customers because they did not meet the payment obligations over each of the last 36 months. Dev
> Consider the ANOVA table that follows. a. Determine the standard error of estimate. About 95% of the residuals will be between what two values? b. Determine the coefficient of multiple determination. Interpret this value. c. Determine the co
> Research at the University of Toledo indicates that 50% of students change their major area of study after their first year in a program. A random sample of 100 students in the College of Business revealed that 48 had changed their major area of study af
> Cincinnati Paint Company sells quality brands of paints through hardware stores throughout the United States. The company maintains a large sales force who call on existing customers and look for new business. The national sales manager is investigating
> The table below reports the earnings per share of common stock for Home Depot Inc. for 2003 through 2015. Develop an index, with 2003 as the base, for earnings per share for years 2004 through 2015. Year Earnings per Share Year Eamings per Share 200
> Under what conditions should the Kruskal-Wallis test be used instead of the Wilcoxon rank-sum test?
> In a particular chi-square goodness-of-fit test, there are six categories and 500 observations. Use the .01 significance level. a. How many degrees of freedom are there? b. What is the critical value of chi-square?
> Describe the difference between an attribute control chart and a variable control chart.
> Tim Waltzer owns and operates Waltzer’s Wrecks, a discount car rental agency near Cleveland Hopkins International Airport. He rents a wreck for $20 a day. He has an arrangement with Landrum Leasing to purchase used cars at $6,000 each.
> The proprietor of the newly built White Mountain Ski and Swim Lodge has been considering purchasing or leasing several snowmobiles for the use of guests. The owner found that other financial obligations made it impossible to purchase the machines. Snowmo
> The quality assurance department at Malcomb Products must either inspect each part in a lot or not inspect any of the parts. That is, there are two decision alternatives: inspect all the parts or inspect none of the parts. The proportion of parts defecti
> A financial executive for Fidelity Investments lives in Boston but frequently must travel to New York. She can go to New York by car, train, or plane. The cost for a plane ticket from Boston to New York is $200, and it is estimated that the trip takes 30
> The following regression output was obtained from a study of architectural firms. The dependent variable is the total amount of fees in millions of dollars. x1 is the number of architects employed by the company. x2 is the number of engineers employed
> At the beginning of each football season, Team Sports, the local sporting goods store, purchases 5,000 footballs. A sample of 25 balls is selected, and they are inflated, tested, and then deflated. If more than two balls are found defective, the lot of 5
> Swiss Watches, Ltd. purchases watch stems for their watches in lots of 10,000. Their sampling plan calls for checking 20 stems, and if 3 or fewer stems are defective, the lot is accepted. a. Based on the sampling plan, what is the probability that a lot
> Christina Sanders is a member of the women’s basketball team at Windy City College. Last season, she made 55% of her free throw attempts. In an effort to improve this statistic, she attended a summer camp devoted to shooting techniques.
> Use the variables mean amount per transaction and number of associates to forecast net sales. Are these two independent variables reasonable predictors of net sales? What is the R2 value? Is it large? Look at the p-values for each of the independent vari
> Develop a trend equation for the net sales ($ million) for Home Depot. Consider both a linear trend and a nonlinear trend. Which one would you select and why? Given the trend equation you selected, forecast the net sales for 2016 and 2017. Use the follow
> The enrollment in the College of Business at Midwestern University by quarter from 2013 to spring 2017 is: Using the ratio-to-moving-average method: a. Determine the four quarterly indexes. b. Interpret the quarterly pattern of enrollment. Does the sea
> The following is the number of retirees receiving benefits from the State Teachers Retirement System of Ohio from 1996 until 2015. a. Plot the data. b. Determine the least squares trend equation. Use a linear equation. c. Calculate the points for the y
> Sales of roof material, by quarter, for 2010 through 2016, by Carolina Home Construction Inc. are shown below (in $000). a. Determine the typical seasonal patterns for sales using the ratio-to-moving-average method. b. Deseasonalize the data and determ
> The North Valley Real Estate data reports information on homes on the market. a. Determine the proportion of homes that have an attached garage. At the .05 significance level, can we conclude that more than 60% of the homes have an attached garage? What
> At the time she was hired as a server at the Grumney Family Restaurant, Beth Brigden was told, “You can average $80 a day in tips.” Assume the population of daily tips is normally distributed with a standard deviation of $9.95. Over the first 35 days she
> The quarterly production of pine lumber, in millions of board feet, by Northwest Lumber for 2012 through 2016 is: a. Determine the typical seasonal pattern for the production data using the ratio-to-moving-average method. b. Interpret the pattern. c. D
> The production of Reliable Manufacturing Company for 2012 and part of 2013 follows. a. Using the ratio-to-moving-average method, determine the specific seasonals for July, August, and September 2012. b. Assume that the specific seasonal indexes in the
> Listed below is the selling price for a share of PepsiCo Inc. at the close of each year from 1998 to 2015. a. Plot the data. b. Determine the least squares trend equation. c. Calculate the points for the years 2008 and 2013. d. Estimate the selling pri
> Refer to the Baseball 2016 data, which include information on the 2016 Major League Baseball season. The data also include the mean player salary since 1989. a. Use the year 2000 salary as the base period and 100 as the base value to develop a simple ind
> We are making a historical study of the American economy from 1950 to 1980. Data on prices, the labor force, productivity, and the GNP were collected. Note in the following table that the CPI has a base period of 1967, employment is in millions of person
> The National Cable and Telecommunications Association recently reported that the mean number of HDTVs per household in the United States is 2.30 with a standard deviation of 1.474 sets. A sample of 100 homes in Boise, Idaho, revealed the following sample
> John Isaac Inc., a designer and installer of industrial signs, employs 60 people. The company recorded the type of the most recent visit to a doctor by each employee. A recent national survey found that 53% of all physician visits were to primary care ph
> Refer to the Lincolnville School District bus data. a. Select the variable for the number of miles traveled last month. Conduct a hypothesis test to determine whether the mean miles traveled last month equals 10,000. Use the .01 significance level. Find
> Banner Mattress and Furniture Company wishes to study the number of credit applications received per day for the last 300 days. The sample information is reported below. Number of Credit Applications ______Frequency (Number of Days) 0 ………………………………………………
> The North Valley Real Estate data reports information on the homes sold last year. Adam Marty recently joined North Valley Real Estate and was assigned twenty homes to market and show. When he was hired, North Valley assured him that the twenty homes wou
> A recent article reported that a job awaits only one in three new college graduates. The major reasons given were an overabundance of college graduates and a weak economy. A survey of 200 recent graduates from your school revealed that 80 students had jo
> Consider the data in Exercise 10 from Chapter 14 and the regression equation to predict commissions earned. In Exercise 10 from Chapter 14 Cincinnati Paint Company sells quality brands of paints through hardware stores throughout the United States. The
> There are four entrances to the Government Center Building in downtown Philadelphia. The building maintenance supervisor would like to know if the entrances are equally utilized. To investigate, 400 people were observed entering the building. The number
> The publisher of a sports magazine plans to offer new subscribers one of three gifts: a sweatshirt with the logo of their favorite team, a coffee cup with the logo of their favorite team, or a pair of earrings also with the logo of their favorite team. I
> The owners of the Westfield Mall wished to study customer shopping habits. From earlier studies, the owners were under the impression that a typical shopper spends 0.75 hour at the mall, with a standard deviation of 0.10 hour. Recently the mall owners ad
> Compute a simple index for the number of employees for GE using the period 2004–06 as the base. What can you conclude about the change in the number of employees over the period? Use the following information from General Electric Corpo
> The proportion of on-line shoppers who actually make a purchase appears to be relatively constant over time. In 2013, among a sample of 388 on-line shoppers, 160 purchased merchandise. In 2017, for a sample of 307 on-line shoppers, 144 purchased merchand
> Sam Steward is a freelance Web page designer. Listed below are his yearly wages for several years between 2013 and 2016. Also included is an industry index for Web page designers that reports the rate of wage inflation in the industry. This index has a b
> The Trade Union Association of Orlando, Florida, maintains indexes on the hourly wages for a number of the trades. Unfortunately, the indexes do not all have the same base periods. Listed below is information on plumbers and electricians. Shift the base
> You are employed by the state bureau of economic development. There is a demand for a leading economic index to review past economic activity and to forecast future economic trends in the state. You decide that several key factors should be included in t
> Refer to the Baseball 2016 data, which report information on the 2016 Major League Baseball season. a. Rank the teams by the number of wins and their total team salary. Compute the coefficient of rank correlation between the two variables. At the .01 sig
> The waiting time for customers at MacBurger Restaurants follows a normal distribution with a population standard deviation of 1 minute. At the Warren Road MacBurger, the quality-assurance department sampled 50 customers and found that the mean waiting ti
> A series of questions on sports and world events was asked of 14 randomly selected young adult naturalized citizens. The results were translated into sports and world events “knowledge” scores. The scores were: a. De
> Professor Bert Forman believes the students who complete his examinations in the shortest time receive the highest grades and those who take the longest to complete them receive the lowest grades. To verify his suspicion, he assigns a rank to the order o
> The production manager of MPS Audio Systems Inc. is concerned about the idle time of workers. In particular, he would like to know if there is a difference in the idle minutes for workers on the day shift and the evening shift. The information below is t
> During recent seasons, Major League Baseball has been criticized for the length of the games. A report indicated that the average game lasts 3 hours and 30 minutes. A sample of 17 games revealed the following times to completion. (Note that the minutes h
> The objective of a community research project is to determine whether women are more community conscious before marriage or after 5 years of marriage. A test designed to measure community consciousness was administered to a sample of nine women before ma
> Research in the gaming industry showed that 10% of all slot machines in the United States stop working each year. Short’s Game Arcade has 60 slot machines and only 3 failed last year. At the .05 significance level, test whether these data contradict the
> IBM Inc. is going to award a contract for fine-line pens to be used nationally in its offices. Two suppliers, Bic and Pilot, have submitted bids. To determine the preference of office personnel, a preference test was conducted using a randomly selected s
> Refer to the Baseball 2016 data, which report information on the 30 Major League Baseball teams for the 2016 season. Let the number of games won be the dependent variable and the following variables be independent variables: team batting average, team Ea
> According to a study by the American Pet Food Dealers Association, 63% of U.S. households own pets. A report is being prepared for an editorial in the San Francisco Chronicle. As a part of the editorial, a random sample of 300 households showed 210 own p
> Think about the figures from the previous exercise. Add a new variable that describes the potential interaction between the loan amount and the number of payments made. Then do a test of hypothesis to check if the interaction is significant. In Previous
> Cellulon, a manufacturer of home insulation, wants to develop guidelines for builders and consumers on how the thickness of the insulation in the attic of a home and the outdoor temperature affect natural gas consumption. In the laboratory, it varied the
> Suppose Texas A & M University—Commerce has five scholarships available for the women’s basketball team. The head coach provided the two assistant coaches with the names of 10 high school players with potential to
> The director of special events for Sun City believed that the amount of money spent on fireworks displays for the 4th of July was predictive of attendance at the Fall Festival held in October. She gathered the following data to test her suspicion. Dete
> 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. The mean expense is $52.0 million and the s
> The Conch Café, located in Gulf Shores, Alabama, features casual lunches with a great view of the Gulf of Mexico. To accommodate the increase in business during the summer vacation season, Fuzzy Conch, the owner, hires a large number of serv
> Many regions in North and South Carolina and Georgia have experienced rapid population growth over the last 10 years. It is expected that the growth will continue over the next 10 years. This has motivated many of the large grocery store chains to build
> Rutter Nursery Company packages its pine bark mulch in 50-pound bags. From a long history, the production department reports that the distribution of the bag weights follows the normal distribution and the standard deviation of the packaging process is 3
> A market researcher is studying on-line subscription services. She is particularly interested in what variables relate to the number of subscriptions for a particular on-line service. She is able to obtain the following sample information on 25 on-line s
> A recent national survey found that parents read an average (mean) of 10 books per month to their children under five years old. The population standard deviation is 5. The distribution of books read per month follows the normal distribution. A random sa
> In recent times, with mortgage rates at low levels, financial institutions have had to provide more customer convenience. One of the innovations offered by Coastal National Bank and Trust is online mortgage applications. Listed below are the times, in mi
> A regional planner is studying the demographics of nine counties in the eastern region of an Atlantic seaboard state. She has gathered the following data: a. Is there a linear relationship between the median income and median age? b. Which variable is
> A sample of 64 observations is selected from a normal population. The sample mean is 215, and the population standard deviation is 15. Conduct the following test of hypothesis using the .025 significance level. H0: μ ≥ 220 H1: μ < 220 (a) Is this a one-
> Mike Wilde is president of the teachers’ union for Otsego School District. In preparing for upcoming negotiations, he is investigating the salary structure of classroom teachers in the district. He believes there are three factors that
> Hugger Polls contends that an agent conducts a mean of 53 in-depth home surveys every week. A streamlined survey form has been introduced, and Hugger wants to evaluate its effectiveness. The number of in-depth surveys conducted during a week by a random
> Nine observations were randomly selected from population A and eight observations were randomly selected from population B. The populations are not normally distributed. Use the .05 significance level, a two-tailed test, and the Wilcoxon rank-sum test to
> Suppose that the sales manager of a large automotive parts distributor wants to estimate the total annual sales for each of the company’s regions. Five factors appear to be related to regional sales: the number of retail outlets in the
