  Fall Semester 2003

Midterm One: What to study.
Here are examples of questions you can expect on the written exam:

1. What is descriptive statistics?

2. How is that different from inferential statistics?

3. What is univariate statistics?

4. Define the following terms: frequency, cumulative frequency, percentage, and cumulative percentage.

5. Define the following terms: pth percentile, quartiles, interquartile range? What does the interquartile range indicate (roughly)?

6. What is a probability distribution?

7. Define observation, sample, and random sample.

8. State the Central Limit Theorem.

9. Here's what they reviewed for the midterm last year. Questions in QuizSite (included) are also fair game.

10. Suppose that you are conducting a survey on the cost of a medical procedure as part of research on health care reform. The cost of the procedure follows the normal distribution with a standard deviation of 1000. After sampling 50 different hospitals at random, you calculate the average cost to be \$5,500. What is the 90% confidence interval for the value of the mean cost of all hospitals? Explain your answer. (see page 212 in your book).

11. You work at a plant that manufactures resistors. Previous studies have shown that the number of defective resistors in a batch follows a normal distribution with a mean of 50 and a standard deviation of 15. A new process has been proposed that will reduce the number of defective resistors, saving the plant money. You put the process in place and create a sample of 25 batches. The average number of defects in a batch is 45. Does this prove that the new process reduces the number of defective resistors, or is 45 simply a random aberration, and the process does not make any difference at all? Explain. (see page 218 in your book)

12. The college administration claims that students should not expect to spend more than an average \$200 each semester for books. A student associated with the school newspaper decides to investigate this claim and interviews 25 randomly selected students. The average spent by the 25 students is \$200, and the standard deviation of these purchases is \$50. Is this significant evidence that the statement from the administration is wrong? Explain. (see page 226 in your book)

Last updated: Nov 18, 2003, by Adrian German (for A113)