Exam 18: A Roadmap for Analyzing Data

A survey was conducted to determine how people rated the quality of programming available on television. Respondents were asked to rate the overall quality from 0 (no quality at all)to 100 (extremely good quality). A cumulative percentage polygon (ogive)can be used to present this information.

An agronomist wants to compare the crop yield of 3 varieties of chickpea seeds. She plants all 3 varieties of the seeds on each of 5 different patches of fields. She then measures the crop yield in bushels per acre. Which of the following tests will be the most appropriate to find out if there is any difference in crop yield among the 3 varieties?

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. Which of the following tests will be the most appropriate to find out if the primary specialty and the origin of medical school degree interact to affect the charges?

An agronomist wants to compare the crop yield of 3 varieties of chickpea seeds. She plants all 3 varieties of the seeds on each of 5 different patches of fields. She then measures the crop yield in bushels per acre. She has found out that the different varieties do have an impact on crop yield. Which of the following tests will be the most appropriate to find out which variety will produce the highest yield?

The use of preservatives by food processors has become a controversial issue. Suppose 2 preservatives are extensively tested and determined safe for use in meats. A processor wants to compare the preservatives for their effects on retarding spoilage. They will choose to use the preservative that can keep the meat fresh for the longest amount of time. Suppose 15 cuts of fresh meat are treated with preservative I and 15 are treated with preservative II, and the number of hours until spoilage begins is recorded for each of the 30 cuts of meat. Suppose the variability of the number of hours until spoilage is the same for meat treated by both preservatives but the normal probability plots reveal that the number of hours until spoilage is right-skewed for the 15 cuts treated by preservative I and left-skewed for the 15 cuts treated with preservative II. Which of the following tests will be the most appropriate?

Four surgical procedures currently are used to install pacemakers. If the patient does not need to return for follow-up surgery, the operation is called a "clear" operation. A heart center wants to compare the 4 procedures and collects the following numbers of patients from their own records: Procedure A B C D Total Clear 27 41 21 7 96 Retur1 11 15 9 11 46 Total 38 56 30 18 142 Which of the following tests will be the most appropriate to find out which of the 4 procedures is the most effective?

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.

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 Paso Robles wine producer wanted to forecast the cases of Merlot wine sold. The number of cases of merlot wine sold in a 28-year period was collected. Which of the following would be the most appropriate analysis to perform?

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?

A sample of 100 fuses from a very large shipment is found to have 10 that are defective. Based on this information, which of the following will you construct to learn about the proportion of fuses that are defective?

A researcher randomly sampled 30 graduates, 18 males and 12 females, of an MBA program and recorded data concerning their starting salaries. Of primary interest to the researcher was the effect of gender on starting salaries. Statistics of the mean salaries of the females and males in the sample were computed. The sample standard deviations suggest that the variability of starting salaries of the two groups is almost the same. Suppose the starting salaries from both groups can be considered as normally distributed. Which of the following tests will be the most appropriate?

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?

An agronomist wants to compare the crop yield of 3 varieties of chickpea seeds. She plants all 3 varieties of the seeds on each of 5 different patches of fields. She then measures the crop yield in bushels per acre. Which of the following tests will be the most appropriate to find out if the different patches is advantageous in reducing the random error?

A professor of economics at a small Texas university wanted to determine what year in school students were taking his tough economics course. Data were collected on the class status ("freshman," "sophomore," "junior" or "senior")of 50 students enrolled in one of his economics course. A side-by-side bar chart can be used to present this information.

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?

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?

A Paso Robles wine producer wanted to forecast the cases of Merlot wine sold. The number of cases of merlot wine sold in a 28-year period was collected. Which of the following would be the most appropriate analysis to perform?

Four surgical procedures currently are used to install pacemakers. If the patient does not need to return for follow-up surgery, the operation is called a "clear" operation. A heart center wants to compare the 4 procedures and collects the following numbers of patients from their own records: Procedure A B C D Total Clear 27 41 21 7 96 Retur1 11 15 9 11 46 Total 38 56 30 18 142 Which of the following tests will be the most appropriate to find out whether the 4 procedures are equally effective?