AP Statistics : Data Collection

Study concepts, example questions & explanations for AP Statistics

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Example Questions

Example Question #3 : How To Establish Blind Experiments

Which of the following is an example of a single-blind experiment? 

Possible Answers:

An experiment in which the researchers and test subjects are aware of who is receiving a placebo and who is receiving a therapy.

An experiment in which the researchers are aware of who is receiving a placebo and who is receiving a therapy, but the test subjects are unaware.

Two of the answers are correct

An experiment in which the test subjects are aware of who is receiving a placebo and who is receiving a therapy, but the researchers are unaware. 

An experiment in which the researchers and test subjects are unaware of who is receiving a placebo and who is receiving a therapy. 

Correct answer:

Two of the answers are correct

Explanation:

In a single-blind experiment, one group (either the researchers or the test subjects) must be blinded while the other group is aware of who is receiving a placebo and who is receiving a therapy.

The following two examples are correct:

-An experiment in which the test subjects are aware of who is receiving a placebo and who is receiving a therapy, but the researchers are unaware. 

-An experiment in which the researchers are aware of who is receiving a placebo and who is receiving a therapy, but the test subjects are unaware.

Example Question #4 : How To Establish Blind Experiments

Alpha Corporation developed a new pill to treat elevated glucose levels. They want to test the efficiency of the pill to lower glucose levels by gathering a sample of people with high glucose and giving them either:

1) A daily dose of their new pill ("Experimental Group")

2) A daily placebo pill that looks the same but does not do anything ("Placebo Group")

 

How can they make this a "Blind Study"?

Possible Answers:

Keep the participant identities hidden from the experimenters permanently.

Give the pill to people with high blood glucose and low blood glucose.

Give all participants both pills.

Randomly sort people into the Experimental or Placebo groups, without letting them know which pill they received.

Blindfold the participants while they take the pills.

Correct answer:

Randomly sort people into the Experimental or Placebo groups, without letting them know which pill they received.

Explanation:

A blind experiment is one in which the participant does not know which experimental group they are in-- which is accomplished by not letting them know if they are in the Experimental or Placebo group.

 

Example Question #5 : How To Establish Blind Experiments

A drug company wants to test a new pill that should make people's nails grow twice as quickly as normal. How can they make the study a blind study?

Possible Answers:

Give one group of people the actual pill and one group a placebo, but don't tell the participants which pill they are receiving.

This test cannot be done as a blind study.

Give half participants the placebo pill and tell them they had the actual pill, and give the rest the actual pill but tell them they have the placebo pill.

Give all participants the placebo pill and measure nail growth.

Give all participants the actual pill and measure nail growth.

Correct answer:

Give one group of people the actual pill and one group a placebo, but don't tell the participants which pill they are receiving.

Explanation:

In order for a study to be "blind," the participants can't know which group they are sorted into. For a study to be double-blind, which is even better, the researchers should also be blind to which group participants are in until the study is completed.

Example Question #1 : How To Conduct Matched Pairs Experiments

An company wants to test how much a fuel additive improves the fuel efficiency of cars and has  cars of various makes and models available to test. Which experimental design would be most appropriate?

Possible Answers:

Matched pairs -test

One-sample proportion -test

Two-sample -test

Two-sample -test

Chi-square test of association

Correct answer:

Matched pairs -test

Explanation:

A matched pairs design t test is the best choice because it will compare the effectiveness of the fuel additive by looking at the means differences of two sample sets where the only variable that is changed from one test to the other test is the introduction of the fuel additive. It makes no sense to compare the performance of, for example, a Ford Mustang with the additive against a Toyota Prius hybrid without the additive. It becomes crucial to compare fuel efficiency with and without the fuel additive for each car.

Example Question #1 : How To Conduct Matched Pairs Experiments

For which of these experiments would a matched pairs design not be ideal?

Possible Answers:

Evaluating effectiveness of a new type of oil filter in various cars.

Evaluating effectiveness of a test preparation regimen.

Comparing effectiveness of two coaches and their methods.

Comparing strength of right arms against strength of left arms.

Evaluating the effectiveness of a diet.

Correct answer:

Comparing effectiveness of two coaches and their methods.

Explanation:

Remember that a matched pairs design tends to involve "before and after" or "with and without" or "left and right" using the same experimental units.

Therefore comparing effectiveness of two coaches and their methods would not be an experiment for the matched pairs design.

Example Question #1 : How To Define A Survey Population

A company asks you to conduct a survey to discover what consumers generally want. What should the survey population be? 

Possible Answers:

All possible consumers

All of the company's customers

Past consumers

Future consumers

Correct answer:

All possible consumers

Explanation:

The company wants a survey on what consumers want. That means they are interested in all possible consumers. The other groups are too specific. 

Example Question #22 : Data Collection

Your AP Statistics teacher asks you to conduct a survey to determine the most popular cereal brand at your high school. Which of the following should be the survey population in your study? 

Possible Answers:

All high school students in the United States 

All students in your high school

Students in your AP Statistics Class

All high school students in your city

Students in your grade level

Correct answer:

All students in your high school

Explanation:

Since your teacher has asked that you determine the most popular cereal brand at your high school, the survey population should be limited to only your high school. Other students' preferences of cereal brands around the nation will have no impact on the survey results.

Additionally, surveying only students in your AP Statistics class or only students in a particular grade level would not be representative of all students in your high school. Therefore, the correct survey population is all students in your high school. 

Example Question #23 : Data Collection

Shawn would like to determine what the most popular television channel is in his town, called Hearne. 

Which of the following would be an appropriate target population for the survey? 

Possible Answers:

Attendees of a mass at a local Church

Residents of the town whose contact information can be found in the local directory

Purchasers of a television at the local electronics store 

Shoppers at the local grocery store

Students at the local high school 

Correct answer:

Residents of the town whose contact information can be found in the local directory

Explanation:

Since Shawn would like to know the most popular television channel in his town, he must include all residents of the town in his target population. The sample must come from the directory and each person in the directory should have an equal chance of being selected. The incorrect options are too narrowly focused and are not representative of the town.

Example Question #24 : Data Collection

Which of the following is a continuous variable?

i. The average weight of a newborn puppy

ii. The number of snow days during the last month

iii. The amount of time that it takes to read a book

 

Possible Answers:

None of the above

i and ii

i and iii

ii and iii

i only

Correct answer:

i and iii

Explanation:

A continuous variable can take on an infinite continuum of possible real number values. Weight and the amount of time to read a book are continuous because it is impossible to write down all the distinct potential values. 

Example Question #25 : Data Collection

For which of these is a binomial probability model most reasonable?

Possible Answers:

The number of cards drawn from a deck until the two jokers are drawn. 

The number of times a randomly selected college student has gone to the beach in the last year. 

The number of people surveyed until someone who has no pets is found. 

The colors of the gummy bears in a particular bag of gummy bears from a randomly selected store rack. 

The number of times, out of  attempts, that a player can throw a basketball through the hoop from  feet away.

Correct answer:

The number of times, out of  attempts, that a player can throw a basketball through the hoop from  feet away.

Explanation:

A binomial model counts the number of successes out of a specific number of attempts at a task when each attempt has a constant probability of success. The correct choice is the one that specifies the number of attempts. 

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