AP Statistics / Mr. Hansen	Name: _______________________________________
11/8/2006	Mr. Hansen’s use only (bonus point for spare batteries): _______

Quest through p. 276 in text, Version 1

Please read: Calculator is OK throughout. However, per your vote, no written or computer-printed notes are permitted today. Scoring is 5 points per question with no partial credit (70 points total). This is a fairly hard quest.

	For questions 1 and 2, please read this methodology paragraph from an abstract of a recent study. [Source: www.neurology.org, 11/8/2006.] Methods: The authors conducted a prospective cohort study of 3,718 participants, aged 65 years and older of the Chicago Health and Aging Project. Participants completed a food frequency questionnaire and were administered at least two of three cognitive assessments at baseline, 3-year, and 6-year follow-ups. Cognitive function was measured using the average z-score of four tests: the East Boston Tests of immediate memory and delayed recall, the Mini-Mental State Examination, and the Symbol Digit Modalities Test.
1.	Write the conclusions of the study. (There were two.)
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2.	Was a cause-and-effect relationship between diet choices and cognitive decline shown in the study? ____ Why or why not? _______________________________________________________
3.	Yesterday, in the refectory, the Albanian staff distributed a survey in an attempt to gain humorous insights that could be used in the 2007 STA yearbook. For example, one of the questions asked about “your favorite class ever,” and another asked, “What is your favorite movie of the year?” What can you say about this survey? (A) It uses randomized design. (B) It is of no value in gathering anecdotal data. (C) It is a worthwhile exercise despite suffering from voluntary response bias. (D) It suffers from response bias and is of no value. (E) It suffers from both response bias and bias caused by wording of the questions.
4.	Yesterday, Mr. Hansen obtained a flu shot from Nurse Stone. Since flu vaccines are prepared using egg protein, there is always a small chance of an allergic reaction. Because Mr. Hansen had two sores on his left arm, Ms. Stone asked him to bare his right arm instead. She was concerned about possible (A) confounding (B) common response (C) experimental error (D) extrapolation (E) residual plots
5.	On Monday, before the election, news reports indicated that of all the recent polls in the Virginia U.S. Senate race between Allen and Webb, most of the polls (all but two, in fact) were not worth reporting. Why not?
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6.	What constitutes statistical proof of cause and effect? (Word your answer without using the term statistical significance or statistically significant.)
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7.	What is meant by the term placebo effect?
	(A) response bias (B) hidden bias caused by a conflict of interest (C) hidden bias caused by unknown factors, possibly including conflict of interest or a desire to please (D) voluntary response bias (E) either (A) or (D)
8.	After performing a LSRL fit on the domain [0, 8], we note that r = –.844, and the residual plot looks random with nearly equally spaced x values. Can we use y to predict x if the y value in question is between and ? (A) No, because < . (B) No, because there is no cause-and-effect relationship proved. (C) No, because this would be an example of extrapolation. (D) No, because although one can use x to predict y, one cannot use y to predict x. (E) Yes.
9.	The abbreviation SRS stands for ________________  ________________  ________________ .
10.	Explain (briefly) how you might obtain an SRS of 5 STAtistics students from a class of 15.
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11.	Suicide among teenagers is relatively rare, but it is common among elderly men. To what do you attribute the fact that most people find this information surprising? A short answer (sentence fragment) will suffice, or you may write a sentence or two.
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12.	Explain what is meant by “gastric freezing” (from the textbook reading).
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13.	Explain why a proper experiment must always include a control. If possible, use your answer to #12 as an illustrative example.
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14.	What is the basic flaw (one word answer) in a survey of teenagers that involves calling them at home during the time of 2:30 to 4:30 p.m. to see how interested they are in sports?