AP Statistics Unit 3 Review

In order to use samples to estimate something from the population, the sample should be _________________ the population.

• exactly the same as

• nothing like

• representative of

• larger than

In a certain school, students can choose whether to eat in the school’s cafeteria. A reporter working for the school’s newspaper polled students on their reactions to changes in the menu at the cafeteria. For each student leaving the cafeteria in one 20-minute time period, the reporter used a die to determine whether to stop the student and ask how he or she felt about the new menu. In the reporter’s article it was stated that a random sample of the students showed that 23% of the school’s student population was happy with the new menu. Which of the following statements is true?

• Because each student leaving the cafeteria was randomly selected and could choose to answer or not, this is a random sample of the student population, and the 23% is an accurate measurement of the school population’s view of the new menu.

• Because students self-selected whether to eat in the cafeteria, the sampling method might be biased and the sample might not be representative of all students in the school.

• The survey would have been more effective if the reporter had collected the data in one 10-minute time period rather than in one 20-minute time period.

• The survey would have been more effective if students who cared about the food could have called the reporter to tell how they felt about the new menu, so that only students with opinions on the subject would have been surveyed.

• Because no treatment was imposed on the students eating in the cafeteria, one cannot make any conclusions about the new menu.

Anything in a survey design that influences responses is called _______. (Choose the best answer)

• response bias

• voluntary response

• non response

• undercoverage

Which type of study has treatments that are imposed on subjects?

• observational study

• experiment

An apartment complex is made up of 10 buildings with 12 apartments in each building. The manager wants to select a sample of apartments to measure interest in a proposed improvements to the swimming pool. If the manager selects 20 apartments by randomly selecting 2 apartments from each building, what kind of sample did the manager obtain?

• Convenience sample

• Systematic random sample

• Simple random sample

• Stratified random sample

• Cluster random sample

A market research company wishes to find out whether the population of students at a university prefers Starbucks or Dunkin Donuts. A random sample of students is selected, and each student is asked first to try both but the order they try them is randomly decided with a coin toss (heads: Starbucks, then Dunkin. tails: vice versa). They then indicate which brand they prefer. This is an example of

• completely randomized experiment

• observational study

• stratified sample

• matched pairs experiment

The two graduates with the greatest GPA from each of 14 randomly selected law schools were recruited to investigate a new method of preparation for a law exam. For each school, one student was randomly assigned to prepare using the standard method and the other student was assigned to prepare using the new method. At the end of the preparation, all 28 students were given the same exam, and their scores were recorded. Which of the following best describes why a matched-pairs design is an appropriate design for the investigation?

• Each graduate was randomly assigned to one method.

• The law schools were randomly selected.

• Each method served as a block.

• The sample size was less than 30.

• Each law school served as a block, and the graduates were paired within each law school and randomly assigned to one of the two methods.

To investigate the effectiveness of an herbal medication for pain relief, a researcher randomly selected 80 patients who were undergoing physical therapy while recovering from an injury. Of the patients, 40 had knee injuries, 16 had arm injuries, and 24 had foot injuries. The researcher will use two treatments for the investigation: the herbal medication and a standard medication. After the patients are on the medication for two weeks, the amount of pain reduction will be measured for each patient. Which of the following best describes why a randomized block design is appropriate for the investigation?

• The 80 patients were selected at random from all patients undergoing physical therapy while recovering from an injury.

• The sample size was greater than 30.

• Each patient will be randomly assigned to either the herbal medication or the standard medication.

• Blocking on injury type will help to separate natural variability from differences due to injury type.

• Each patient assigned to the herbal medication will be paired with a patient assigned to the standard medication.

What kind of experiment is shown in the picture?

• Randomized Block Design

• Completely Randomized Design

• Matched Pairs

What kind of experiment is shown?

• Matched Pairs

• Block Design

• Completely Randomized Design