Exam 19: Statistical Analysis Scenarios and Distributions

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 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.

Suppose the probability of a power outage at a nuclear power plant on a single day is the same every day of the year. Also the probability of having a power outage on a single day does not increase or decrease the probability of a power outage on another day. Which of the following distributions would you use to figure out the probability that a power outage will occur next Monday?

To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. There is evidence that the before and after exam scores are not normally distributed. Which of the following tests will be the most appropriate?

You have 5 stocks in your investment portfolio. You want to keep track of your portfolio's performance over the last 2 years. You have data on each of the stock's average price and the number of shares of each stock for every day of the last 2 years. Which of the following would be the most appropriate analysis to perform?

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?

A medical doctor is involved in a $1 million malpractice suit. He can either settle out of court for $250,000 or go to court. If he goes to court and loses, he must pay $825,000 plus $175,000 in court costs. If he wins in court the plaintiffs pay the court costs. Which of the following would be the most appropriate analysis to 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.

Suppose the light bulbs in a factory burn out at a rate of 50 bulbs per month. Which of the following distributions would you use to figure out the probability that the next two light bulbs will burn out 2 days apart?

Suppose that past history shows that 60% of college students prefer coca-cola. A sample of 10,000 students is to be selected. Which of the following distributions would you use to figure out the probability that at least half of them will prefer coca-cola?

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 certain type of rare gem serves as a status symbol for many of its owners. In theory, for low prices, the demand increases and it decreases as the price of the gem increases. However, experts hypothesize that when the gem is valued at very high prices, the demand increases with price due to the status owners believe they gain in obtaining the gem. Data on price and quantity sold were collected for a sample of 35 rare gems of this type. 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 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 senior who will bring at least one guest to a luncheon?

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 Return 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?

The probability that a particular brand of smoke alarm will function properly and sound an alarm in the presence of smoke is 0.8. You have 5 such alarms in your home and they operate independently. Which of the following distributions would you use to figure out the probability that all of them will function properly in case of a fire?

Suppose that past history shows that 6% of college students prefer Brand A Cola. A sample of 10,000 students is to be selected. Which of the following distributions would you use to figure out the probability that at least half of them will prefer Brand A cola?

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?

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 what the most popular number of guests brought by the graduating seniors is. Which of the following will 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?

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?