Exam 18: A Roadmap for Analyzing Data

A realtor wants to compare the variability of sales-to-appraisal ratios of residential properties sold in four neighborhoods (A,B,C,and D).Four properties are randomly selected from each neighborhood and the ratios recorded for each were collected.Which of the following tests will be the most appropriate?

Private colleges and universities rely on money contributed by individuals and corporations for their operating expenses.Much of this money is put into a fund called an endowment,and the college spends only the interest earned by the fund.A recent survey of 8 private colleges in the United States collected information on the endowment amount.Based on this information,which of the following will you construct to learn about the mean endowment of all private colleges in the United States?

Every spring semester,the School of Business coordinates with local business leaders a luncheon for graduating seniors,their families,and friends.Corporate sponsorship pays for the lunches of each of the seniors,but students have to purchase tickets to cover the cost of lunches served to guests they bring with them.Data on the number of guests each graduating senior invited to the luncheon from 500 graduating seniors last year were collected.Based on this information,which of the following will you construct to learn about the percentage of seniors who will bring at least one guest to a luncheon?

The superintendent of a school district wanted to predict the percentage of students passing a sixth-grade proficiency test.She obtained the data on percentage of students passing the proficiency test (% Passing),daily mean of the percentage of students attending class (% Attendance),mean teacher salary in dollars (Salaries),and instructional spending per pupil in dollars (Spending)of 47 schools in the state.She believed that holding everything else constant,instructional spending per pupil had a positive but decreasing impact on percentage.Which of the following would be the most appropriate analysis to perform?

Data on the amount of money made in a year by 1,000 families in a small town were collected.You want to know how much each family will get if the money made by all the 1,000 families is pooled together and then evenly redistributed back to them.Which of the following would you compute?

Data on the amount of money made in a year by 1,000 families in a small town were collected.You want to know if the money made is normally distributed.Which of the following would you use?

Data were collected on the amount of detergent used in gallons in a month by 25 drive-through car wash operations in Phoenix.You can use a time-series plot to present this information.

A supplier of silicone sheets for producers of computer chips wants to evaluate her manufacturing process.She takes samples of size 5 from each day's output and counts the number of blemishes on each silicone sheet for 20 days consecutive days.Which of the following would be the most appropriate analysis to perform?

A physician and president of a Tampa Health Maintenance Organization (HMO)are attempting to show the benefits of managed health care to an insurance company.The physician believes that certain types of doctors are more cost-effective than others.To investigate this,the president obtained independent random samples of 20 HMO physicians from each of 4 primary specialtiesGeneral Practice (GP),Internal Medicine (IM),Pediatrics (PED),and Family Physicians (FP)and recorded the total charges per member per month for each.A second variable which the president believes influences total charges per member per month is whether the doctor is a foreign or US medical school graduate.To investigate this,the president also collected data on 20 foreign medical school graduates in each of the 4 primary specialty types described above.So information on charges for 40 doctors (20 foreign and 20 US medical school graduates)was obtained for each of the 4 specialties.The president has already found out that specialty types and origin of the medical degree do not interact to affect the charges.Which of the following tests will be the most appropriate to find out if the primary specialty affects the charges?

At a meeting of information systems officers for regional offices of a national company,a survey was taken to determine the number of employees the officers supervise in the operation of their departments,where X is the number of employees overseen by each information systems officer.A stem-and-leaf display can be used to present this information.

An airline wants to select a computer software package for its reservation system.Four software packages (1,2,3,and 4)are commercially available.An experiment is set up in which each package is used to make reservations for 5 randomly selected weeks and data on the number of passengers that are bumped over a month are collected.(A total of 20 weeks was included in the experiment.)The variability of the number of passengers that are bumped is found to be roughly the same for the 4 packages.The distribution on the number of passengers that are bumped has been found out to be right-skewed for package 1 and 4,left-skewed for package 2 and normal for package 3.Which of the following tests will be the most appropriate to find out if the mean number of passengers being bumped over a month is the same across the 4 packages?

A powerful women's group has claimed that men and women differ in attitudes about sexual discrimination.A group of 50 men (group 1)and 40 women (group 2)were asked if they thought sexual discrimination is a problem in the United States.Of those sampled,11 of the men and 19 of the women did believe that sexual discrimination is a problem.Which of the following tests will you use to find out if there is any difference in attitudes about sexual discrimination?

The director of a training program wanted to know if a one-week orientation would change the perception of potential clients who would perceive the program as being good.He collected information on the number of clients who would rate the program as being good before and after the orientation.Which of the following tests will be the most appropriate?

The owner of a local nightclub has recently surveyed a random sample of n = 250 customers of the club.She would now like to determine whether or not the mean age of her customers is more than 30.If so,she plans to alter the entertainment to appeal to an older crowd.If not,no entertainment changes will be made.Which of the following tests will you perform to help her make a decision?

A survey claims that 9 out of 10 doctors recommend aspirin for their patients with headaches.To test this claim,a random sample of 100 doctors results in 83 who indicate that they recommend aspirin.Which of the following tests will you perform?

A buyer for a manufacturing plant suspects that his primary supplier of raw materials is overcharging.In order to determine if his suspicion is correct,he contacts a second supplier and asks for the prices on various identical materials.He wants to compare these prices with those of his primary supplier.He collected data on 6 different materials from both suppliers.He believes that the differences are normally distributed.Which of the following tests will be the most appropriate?

A political pollster randomly selects a sample of 100 voters each day for 8 successive days and asks how many will vote for the incumbent.The pollster wishes to see if the percentage favoring the incumbent candidate is too erratic.Which of the following would be the most appropriate analysis to perform?

Data on the amount of time spent studying for a particular exam at a high school were collected for 150 students.You want to know at least how much time half of the students spent studying for that exam.Which of the following would you compute?

A quality control engineer is in charge of the manufacture of computer disks.Two different processes can be used to manufacture the disks.He suspects that the Kohler method produces a greater proportion of defects than the Russell method.He samples 150 of the Kohler and 200 of the Russell disks and finds that 27 and 18 of them,respectively,are defective.If Kohler is designated as "Group 1" and Russell is designated as "Group 2," which of the following tests will you use to find out if the Kohler method is worse than the Russell method?

An airline wants to select a computer software package for its reservation system.Four software packages (1,2,3,and 4)are commercially available.An experiment is set up in which each package is used to make reservations for 5 randomly selected weeks and data on the number of passengers that are bumped over a month are collected.(A total of 20 weeks was included in the experiment.)The variance on the number of passengers that are bumped is found to be roughly the same for the 4 packages.Which of the following tests will be the most appropriate to find out if the mean number of passengers being bumped over a month is the same across the 4 packages?