Unformatted text preview: s of aldrin for River X are given below.
5.1 5.6 3.7 8.0 5.5
8.7 4.6 7.5 5.3 5.3
8.2 4.2 4.3 7.3
4.7 4.8 4.6 Construct a stemplot that displays the concentrations of aldrin for River X.
(c) Describe a characteristic of the distribution of aldrin concentrations in River X that can be seen in the
stemplot but cannot be seen in the boxplot. © 2010 The College Board.
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-6- 2010 AP® STATISTICS FREE-RESPONSE QUESTIONS (Form B)
2. In response to nutrition concerns raised last year about food served in school cafeterias, the Smallville School
District entered into a one-year contract with the Healthy Alternative Meals (HAM) company. Under this
contract, the company plans and prepares meals for 2,500 elementary, middle, and high school students, with a
focus on good nutrition. The school administration would like to survey the students in the district to estimate
the proportion of students who are satisfied with the food under this contract.
Two sampling plans for selecting the students to be surveyed are under consideration by the administration. One
plan is to take a simple random sample of students in the district and then survey those students. The other plan
is to take a stratified random sample of students in the district and then survey those students.
(a) Describe a simple random sampling procedure that the administrators could use to select 200 students from
the 2,500 students in the district.
(b) If a stratified random sampling procedure is used, give one example of an effective variable on which to
stratify in this survey. Explain your reasoning.
(c) Describe one statistical advantage of using a stratified random sample over a simple random sample in the
context of this study. 3. A test consisting of 25 multiple-choice questions with 5 answer choices for each question is administered.
For each question, there is only 1 correct answer.
(a) Let X be the number of correct answers if a student guesses randomly from the 5 ch...
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- Spring '13
- AP Statistics, Simple random sample, AP® STATISTICS FREE-RESPONSE, STATISTICS FREE-RESPONSE QUESTIONS