94. Refer to the Lincolnville school bus data. Set up a variable that divides the age ofthe 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 thisvalue, create a variable for those less than or equal to the median (low maintenance)and those more than the median (high maintenance cost). Finally, develop a table toshow the relationship between maintenance cost and age of the bus.a. What percentage of the buses are less than five years old?b. What percentage of the buses less than five years old have low maintenance costs?c. What percentage of the buses ten or more years old have high maintenance costs?d. Does maintenance cost seem to be related to the age of the bus? Hint: Compare themaintenance cost of the old buses with the cost of the new buses? Would you concludemaintenance cost is independent of the age?
46. Refer to the Lincolnville School District bus data.a. Referring to the maintenance cost variable, develop a box plot. What are the minimum,first quartile, median, third quartile, and maximum values? Are there anyoutliers?b. Using the median maintenance cost, develop a contingency table with bus manufactureras one variable and whether the maintenance cost was above or below themedian as the other variable. What are your conclusions?
25. The Director of Planning for Devine Dining Inc. wishes to study the relationship betweenthe gender of a guest and whether the guest orders dessert. To investigate therelationship, the manager collected the following information on 200 recent customers.GenderDessert Ordered Male Female TotalYes 32 15 47No 68 85 153Total 100 100 200a. What is the level of measurement of the two variables?b. What is the above table called?c. Does the evidence in the table suggest men are more likely to order dessertthan women? Explain why.
The following case will appear in subsequent review sections.Assume that you work in the Planning Department ofthe Century National Bank and report to Ms. Lamberg. Youwill need to do some data analysis and prepare a short writtenreport. Remember, Mr. Selig is the president of the bank,so you will want to ensure that your report is complete andaccurate. A copy of the data appears in Appendix A.6.Century National Bank has offices in several cities inthe Midwest and the southeastern part of the UnitedStates. Mr. Dan Selig, president and CEO, would like toknow the characteristics of his checking account customers.What is the balance of a typical customer?How many other bank services do the checking accountcustomers use? Do the customers use the ATM serviceand, if so, how often? What about debit cards? Whouses them, and how often are they used?To better understand the customers, Mr. Selig askedMs. Wendy Lamberg, director of planning, to select a sampleof customers and prepare a report. To begin, she hasappointed a team from her staff. You are the head of theteam and responsible for preparing the report. You select arandom sample of 60 customers. In addition to the balancein each account at the end of last month, you determine(1) the number of ATM (automatic teller machine) transactionsin the last month; (2) the number of other bank services(a savings account, a certificate of deposit, etc.) thecustomer uses; (3) whether the customer has a debit card(this is a bank service in which charges are made directly tothe customer’s account); and (4) whether or not interest ispaid on the checking account. The sample includes customersfrom the branches in Cincinnati, Ohio; Atlanta,Georgia; Louisville, Kentucky; and Erie, Pennsylvania.1. Develop a graph or table that portrays the checkingbalances. What is the balance of a typical customer?Do many customers have more than $2,000 in theiraccounts? Does it appear that there is a difference inthe distribution of the accounts among the fourbranches? Around what value do the account balancestend to cluster?2. Determine the mean and median of the checking accountbalances. Compare the mean and the medianbalances for the four branches. Is there a differenceamong the branches? Be sure to explain the differencebetween the mean and the median in your report.3. Determine the range and the standard deviation ofthe checking account balances. What do the first andthird quartiles show? Determine the coefficient ofskewness and indicate what it shows. BecauseMr. Selig does not deal with statistics daily, include abrief description and interpretation of the standarddeviation and other measures.
88. Refer to the Lincolnville School District bus data. Prepare a report on the maintenancecost 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 meanmaintenance cost last month? What is the median cost? Is one measure more representativeof the typical cost than the others?b. What is the range of maintenance costs? What is the standard deviation? About 95%of the maintenance costs are between what two values?