Exam 18: Data Analysis Overview

To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. Suppose the before and after exam scores are both 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. 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?

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 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 USA 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 USA 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. He has also found out special types do have an impact on average charges. Which of the following tests will be the most appropriate to find out which primary specialty has the highest charges?

A few years ago, Pepsi invited consumers to take the "Pepsi Challenge." Consumers were asked to decide which of two sodas, Coke or Pepsi, they preferred in a blind taste test. Pepsi was interesting in determining what factors played a role in people's taste preferences. One of the factors studied was the gender of the consumer. Data on the percentage of men and women depicting preference for Pepsi were collected. Which of the following tests will you use to find out if there is any difference in preference between the different gender groups?

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 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 USA 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 USA 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?

An entrepreneur is considering the purchase of a coin-operated laundry. The current owner claims that over the past 5 years, the average daily revenue was $675 with a standard deviation of $75. A sample of 30 days reveals a daily average revenue of $625 and a standard deviation of $70. Which of the following tests will be the most appropriate?

The opinions (classified as "for", "neutral" or "against") of a sample of 200 people broken down by gender about the latest congressional plan to eliminate anti-trust exemptions for professional baseball. You can present this information using a scatter plot.

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 half of the students spent at least how much time studying for that exam. Which of the following would you compute?

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 average number of passengers being bumped over a month is the same across the 4 packages?

A major DVD rental chain is considering opening a new store in an area that currently does not have any such stores. The chain will open if there is evidence that more than 5,000 of the 20,000 households in the area are equipped with DVD players. It conducts a telephone poll of 300 randomly selected households in the area and finds that 96 have DVD players. Which of the following tests will be the most appropriate?

A sample of 200 students at a Big-Ten university was taken after the midterm to ask them whether they went bar hopping the weekend before the midterm or spent the weekend studying, and whether they did well or poorly on the midterm. You can use a contingency table to present this information.

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?

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: Which of the following tests will be the most appropriate to find out whether the 4 procedures are equally effective?

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 average of the percentage of students attending class (% Attendance), average 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?

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 and the number of graduating seniors in each category were collected. You want to know the most popular number of guests brought by the graduating seniors. Which of the following will you compute?

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.

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?

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 pressing this information.