AP Statistics / Mr. Hansen

Name: ____________________________
Collaborated with ____________________

Preliminary Problem

Let a be the number of letters in your last name. Write a here: ____. Let b be the following value based on the first letter of your last name:
A-F 10
G-J 20
K-P 30
Q-S 40
T-Z 50
Write b here: ____. Finally, let s be the number of times that the letter "S" occurs in your last name. Write s here: ____. Compute the number 2a + b + s and write the answer here: _________ . This is a value that you will use several times during the test. Every time you see the symbol à ______ , you are to insert the number that you computed for 2a + b + s. Practice doing this now: à ______. (For example, if your name is Johnson, your value would be 2(7) + 20 + 1 = 35, so you would fill in the number 35 each time you see the special symbol.)

Time limit (IMPORTANT! Read carefully!)

Time limit for each odd-numbered problem is 12 minutes. These problems will be spot-checked only. In other words, you will earn full credit regardless of what you write unless either (a) you write nothing or (b) you write so much that it is obvious that you spent more than 12 minutes. For even-numbered problems, there is no time limit other than the 1:30 p.m. Friday deadline.

1.

(12 minute limit, including reading) Read the two paragraphs at the top of p.566. Explain whether the following statistical analysis is valid: A variety of numeric variables will be gathered from students (height, weight, shoe size, PSAT score, GPA, number of bathrooms at home, number of siblings, number of living grandparents, number of teachers who drive Hondas, etc.). Each data set will then be regressed against family income to determine which pairings give statistically significant linear or nonlinear associations.

2.

Repeat #1, thoughtfully writing 1-2 paragraphs that answer the question. If you are happy with your answer to #1, you need not re-do it. If you wish to build on your answer to #1 without rewriting entirely, use a different color of ink and indicate the colors here: original = _________ , revised = _________ .

3.

(12 minute total limit for both, including reading) Do problems #10.64 and 10.65 on p.567, except that in #10.65, replace all occurrences of the number 77 with your value à ______.

4.

Repeat #3. If you are happy with your answer to #3, you need not re-do it. If you wish to build on your answer to #3 without rewriting entirely, use a different color of ink and indicate the colors here: original = _________ , revised = _________ .

5.

(12 minute limit, including reading) Do problem #10.76 on p.579. You may wish to use a diagram in addition to a verbal explanation.

6.

Repeat #5. If you are happy with your answer to #5, you need not re-do it. If you wish to build on your answer to #5 without rewriting entirely, use a different color of ink and indicate the colors here: original = _________ , revised = _________ .

7.

(12 minute limit, including reading) A 2-sample, 2-sided t test has been designed to have moderate power in detecting a difference of means of size à ______ between two populations, using samples of size n₁ = à ______, n₂ = à ______+8. Qualitatively explain (numeric calculations are not required) the effect on the power of the test that each of the following would have:
(a) Keeping the alternative of interest to be à ______, but halving both sample sizes.
(b) Changing the alternative of interest to be 2à ______ instead of à ______ .
(c) Keeping the alternative of interest to be à ______, and keeping the total number of experimental units the same, but using equal sample sizes.

8.

Repeat #7. If you are happy with your answer to #7, you need not re-do it. If you wish to build on your answer to #7 without rewriting entirely, use a different color of ink and indicate the colors here: original = _________ , revised = _________ .

9.

(12-minute limit, including reading) Do problem #11.59 on pp.648-649, except replace the number 750 with 700+Ã ______ , and replace the number 412 with 400+Ã ______ .

10.

Repeat #9. If you are happy with your answer to #9, you need not re-do it. If you wish to build on your answer to #9 without rewriting entirely, use a different color of ink and indicate the colors here: original = _________ , revised = _________ .

11.

(12-minute limit, including reading) Do problem #11.66 on p.651, except replace the specimen count (40) with your value à ______ .

12.

Repeat #11. If you are happy with your answer to #11, you need not re-do it. If you wish to build on your answer to #11 without rewriting entirely, use a different color of ink and indicate the colors here: original = _________ , revised = _________ .