Chapter 3, Problem 1FDA

Recall from Chapter 1 (see page 34) that the Focus database and Focus sample contain information on the undergraduate students at the University of Wisconsin - Eau Claire (UWEC). Now would be a good time for you to review the discussion about these data sets.

1. a. Open the Focus sample (FocusSample) in the statistical software package of your choice and then obtain the mean and standard deviation of the ages of the sample of 200 UWEC undergraduate students. Are these descriptive measures parameters or statistics? Explain your answer.
2. b. If your statistical software package will accommodate the entire Focus database (Focus), open that worksheet and then obtain the mean and standard deviation of the ages of all UWEC undergraduate students. (Answers: 20.75 years and 1.87 years) Are these descriptive measures parameters or statistics? Explain your answer.
3. c. Compare your means and standard deviations from parts (a) and (b). What do these results illustrate?
4. d. If you used a different simple random sample of 200 UWEC undergraduate students than the one in the Focus sample, would you expect the mean and standard deviation of the ages to be the same as that in part (a)? Explain your answer.
5. e. Open the Focus sample and then obtain the mode of the classifications (class levels) of the sample of 200 UWEC undergraduate students.
6. f. If your statistical software package will accommodate the entire Focus database, open that worksheet and then obtain the mode of the classifications of all UWEC undergraduate students. (Answer: Senior)
7. g. From parts (e) and (f), you found that the mode of the classifications is the same for both the population and sample of UWEC undergraduate students. Would this necessarily always be the case? Explain your answer.
8. h. Open the Focus sample and then obtain the five-number summary of the ACT math scores, individually for males and females. Use those statistics to compare the two samples of scores, paying particular attention to center and variation.
9. i. Open the Focus sample and then obtain the five-number summary of the ACT English scores, individually for males and females. Use those statistics to compare the two samples of scores, paying particular attention to center and variation.
10. j. Open the Focus sample and then obtain boxplots of the cumulative GPAs, individually for males and females. Use those statistics to compare the two samples of cumulative GPAs, paying particular attention to center and variation.
11. k. Open the Focus sample and then obtain boxplots of the cumulative GPAs, individually for each classification (class level). Use those statistics to compare the four samples of cumulative GPAs, paying particular attention to center and variation.