STAtistics / Mr. Hansen	Name: _______________________
4/14/2010	Battery bonus (Mr. Hansen’s use only): _____

Test on Chapters 12 and 13 (Chi-Square and LSRL Tests)

Part I: Multiple Choice, AP-Style. Total point value = 50. Allocate approximately 25 minutes to this section.

Mark the best answer in each case. There is a penalty for wrong guesses, just as on the AP exam. Omitting an answer is permitted, but of course you cannot earn points if you omit the answer. Scores in this section will be “curved.”

Part II: Free Response, non-AP. Total point value = 50. Allocate approximately 25 minutes to this section.

Scores in this section will not be “curved.” Point values are in parentheses in the margin.

11.	A published source (see excerpted question below) claims that the answer is choice A. However, this is not correct! . . . The average GPA of students who worked 20 hours per week is approximately (A) 2.41 (B) 2.55 (C) 2.8 (D) None of the above. (E) The value cannot be determined.
(a) (5)	Explain why many, if not most, students would find A to be an attractive answer choice.
(b) (3)	The correct answer is (circle one) B    C    D    E    .
(c) (5)	Explain (1-2 sentences) why you chose the answer you did.
12.	Consider the following 2-way table.
(a) (5)	What numeric value needs to go in the cell marked by “?” in order to make a table that exhibits perfect independence? Explain your reasoning briefly.
(b) (8)	For the table shown above, suppose that the “?” is replaced by the number 9. Compute the value of the statistic for a test for homogeneity of proportions. Show some work (not all of it, obviously, since that would take a long time).

(c) (24)

Now, for the same table, and with the “?” replaced by the value of 9, perform a test (all steps, except that you are allowed to omit your work this time) for independence. For part (c) only, assume that the results shown in the table are a census of a certain teacher’s students. It is especially critical that you state your null and alternative hypotheses correctly.