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Unit 3

3.9 MC Answers and Review

8 min read•december 12, 2021

AP Statistics 📊

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Answers and Review for Multiple Choice Practice on Collecting Data

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⛔STOP ⛔ Before you look at the answers make sure you gave this practice quiz a try so you can assess your understanding of the concepts covered in Unit 3. Click here for the practice questions: AP Statistics Unit 3 Multiple Choice Questions.

Facts about the test: The AP Statistics exam has 40 multiple choice questions and you will be given 1 hour 30 minutes to complete the section. That means it should take you around 11 minutes to complete 5 questions.

The following questions were not written by College Board and although they cover information outlined in the AP Statistics Course and Exam Description the formatting on the exam may be different.

1. A newspaper writer is gathering data about how many residents enjoy baseball. To gather his data, he interviews people as they walk past the local baseball team's stadium on game day. What type of sample is taken here?

A. Stratified Random Sample

B. Cluster Sample

C. Convenience Sample

D. SRS

Answer: This is a convenience sample because he is only interviewing people who conveniently pass by the baseball stadium (which will lead to a biased overestimate of his question)

📄 Study AP Statistics, Unit 3.4: Potential Problems with Sampling

2. A local mayor is wanting to raise taxes to build a new city hall. In order to determine the support for his initiative, he takes a SRS of 300 adults aged 45-60 and finds that most of them support his tax increase. What type of bias is this?

A. Undercoverage

B. Response Bias

C. Voluntary Response Bias

D. Confounding Bias

Answer: This is an example of undercoverage. This is because the mayor only asks residents in a certain age group, which leaves other age groups underrepresented.

📄 Study AP Statistics, Unit 3.4: Potential Problems with Sampling

3. A researcher wants to know the opinions of workers in education on their pay scale. In order to find the true opinion, the researcher takes a simple random sample of 5000 teachers in the United States and asks them "Do you believe your pay is fair for the work you do?" What is the intended population in this question?

A. All US residents

B. 5000 teachers surveyed

C. All teachers in the US

D. All teachers

Answer: Since our sample was taken randomly from all US teachers, our population is US teachers. We cannot extrapolate our findings to teachers in other nations since they were not included in our sample.

📄 Study AP Statistics, Unit 3.2: Introduction to Planning a Study

4. A researcher wants to know the opinions of workers in education on their pay scale. In order to find the true opinion, the researcher takes a simple random sample of 5000 teachers in the United States and asks them "Do you believe your pay is fair for the work you do?" What is the sample in this question?

A. All US residents

B. 5000 teachers surveyed

C. All teachers in the US

D. All teachers

Answer: Our sample is the 5000 teachers we actually asked.

📄 Study AP Statistics, Unit 3.2: Introduction to Planning a Study

5. A journalist is interested in seeing how college students feel about snow days being converted to e-days where they still have to complete school work virtually. Therefore, she send an email survey to students asking their opinion. What method of sampling is used here?

A. Census

B. Convenience Sample

C. Systematic Sample

D. Voluntary sample

Answer: This is a voluntary sample since we are only sending this to people to answer on a voluntary basis. This would result in bias since only those who feel strongly on the issue would respond.

📄 Study AP Statistics, Unit 3.4: Potential Problems with Sampling

6. A boss wishes to pick a simple random sample from his employees to form a committee. In order to do so, he takes a SRS of 2 from each of the 5 departments at the company and uses those 10 as his committee. What type of sample is this?

A. Cluster Sample

B. Stratified Random Sample

C. Census

D. Convenience Sample

Answer: This is a stratified random sample. This is because the boss has separated his employees into like groups (departments) and then selected a random sample from each of those groups to create his big random sample.

📄 Study AP Statistics, Unit 3.3: Random Sampling and Data Collection

7. In order to determine the amount of students who eat school lunches, a local school principal asks every single student in his school whether they will be eating school lunch or bringing their own. What type of sample is this?

A. Simple Random Sample

B. Stratified Random Sample

C. Census

D. Convenience Sample

Answer: This is a census because it says that every single student was asked the question.

📄 Study AP Statistics, Unit 3.2: Introduction to Planning a Study

8. For a new study being done on the effectiveness of coffee as part of someone's morning routine, the question is asked: "Many studies have shown that coffee is a necessary part of some people's morning routines and has been shown to have positive impacts on their productivity and energy level. Do you feel coffee improves your mood?" What type of bias is represented by this study?

A. Non Response Bias

B. Response Bias

C. Voluntary Response Bias

D. Convenience Sample Bias

Answer: This is an example of response bias. More particularly, this is question wording bias because it is worded in a way that makes people think they should say yes since previous studies have shown this.

📄 Study AP Statistics, Unit 3.4: Potential Problems with Sampling

9. A study is done to test the effects of taking a baby aspirin on general heart health. What is a possible confounding variable in this study?

A. Age of participants

B. Taking placebo

C. Taking baby aspirin

D. Heart health

Answer: The confounding variable in this study is age. Age is not accounted for in the study, but could have affect on our outcomes if not randomly split between the two groups.

📄 Study AP Statistics, Unit 3.2: Introduction to Planning a Study

10. Which of the following is not a component of a well designed experiment?

A. Random Assignment

B. Reallocation of methods

C. Replication

D. Control

Answer: Random assignment, replication and control are all elements of experimental design. Reallocation of methods is....well...something. Not really sure, but we are sure it is not one of the elements of experimental design.

📄 Study AP Statistics, Unit 3.5: Introduction to Experimental Design

11. A study was done in Japan to determine the effectiveness of poison ivy treatments. Participants were called in (and paid) to rub "poison ivy" on their arms and then 2 days later, begin to use a cream to treat the ensuing rash since most participants did break out in a rash. However, none of the participants were exposed to poison ivy, yet many of them still developed a rash. What is this an example of?

A. Single Blind

B. Random Assignment

C. Double Blind

D. Placebo Effect

Answer: This is an example of the placebo effect. Participants had a response to a "fake treatment" because in their mind they were exposed to poison ivy. This experiment wasn't actually done to test poison ivy medications, but rather seeing the validity of the placebo effect.

📄 Study AP Statistics, Unit 3.5: Introduction to Experimental Design

12. Which of the following best describes a randomized block design?

A. Each participant will receive both treatments to minimize or block effects of outside sources

B. Recipients do not know which treatment they are receiving, so their treatment is blocked from them

C. Only selecting certain types of participants, hence blocking outliers from participating

D. Treatments are randomly assigned within each "block" or group of like people

Answer: While all of these make sense, blocking is when you seperate your experimental units into like groups (blocks) and randomly assign treatments within each block. It is similar to a stratified random sample, but for experimental design.

📄 Study AP Statistics, Unit 3.6: Selecting an Experimental Design

13. An entomologist wants to test different growth hormones on ant colonies. In order to do this, he takes 4 different ant colonies and applies the following treatments to each of the 4 colonies: 0 mL, 5 mL, 10 mL and 20 mL and then observes the number of ants 7 days later. What are the experimental units in this study?

A. The ant colonies

B. The ants

C. The growth hormone amounts

D. The number of ants

Answer: The experimental units are the ant colonies. While the ants are reacting to the growth hormones, the actual experimental units are what we specifically apply treatment to, which is the colonies, not the individual ant.

📄 Study AP Statistics, Unit 3.5: Introduction to Experimental Design

14. An entomologist wants to test different growth hormones on ant colonies. In order to do this, he takes 4 different ant colonies and applies the following treatments to each of the 4 colonies: 0 mL, 5 mL, 10 mL and 20 mL and then observes the number of ants 7 days later. Does this experiment have a control and if so, what is it?

A. The 20 mL group

B. The 0 mL group

C. The 5 mL group

D. It does not have a control

Answer: The control of this group is the group receiving 0 mL of growth hormone. It is important to note that they are still receiving a treatment by receiving the 0 mL treatment.

📄 Study AP Statistics, Unit 3.5: Introduction to Experimental Design

15. To help students focus on school work, an educational research firm is studying the effects of music with student retention. In order to test this, students are randomly assigned to a class where music is played softly in the background or a class where no music is played. Student retention of content is the _________ variable.

A. Explanatory

B. Confounding

C. Matched

D. Response

Answer: The student's retention level is the response variable. In other words, this is our dependent variable because it depends on the music treatment that was assigned.

📄 Study AP Statistics, Unit 3.5: Introduction to Experimental Design

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