Question 1

Which of the following best describes a simple random sample?

Accepted Answer

A sample where every possible sample of the same size $$n$$ has the same chance of being chosen.

Question 2

A pharmaceutical company wants to test a new drug. They randomly assign patients to receive either the drug or a placebo, and neither the patients nor the administering doctors know who receives which. What type of experimental design is this?

Accepted Answer

Double-blind experiment

Question 3

Which of the following is an example of a lurking variable in an observational study?

Accepted Answer

A variable that is not included in the study but affects the variables being studied.

Question 4

A researcher divides a city into neighborhoods, randomly selects five neighborhoods, and surveys every household in those neighborhoods. What sampling method is being used?

Accepted Answer

Cluster sampling

Question 5

Which of the following best describes a retrospective study?

Accepted Answer

Data are collected from a past time period by going back in time.

Question 6

In which scenario is confounding most likely to occur?

Accepted Answer

When two or more variables' effects cannot be separated.

Question 7

A polling organization selects every 10th person from a list of registered voters. What type of sampling is this?

Accepted Answer

Systematic sampling

Question 8

Which of the following is a key advantage of using randomization in experimental design?

Accepted Answer

It uses chance to create groups that are similar, reducing bias.

Question 9

A researcher wants to compare the effectiveness of two diets. She matches participants in pairs based on age and gender, then randomly assigns one from each pair to each diet. What design is this?

Accepted Answer

Matched pairs design

Question 10

Which of the following is an example of a nonsampling error?

Accepted Answer

Entering data incorrectly during analysis.

Question 11

A hospital administrator wants to survey patient satisfaction. She divides patients into groups based on the department they visited and randomly selects 20 patients from each department. What sampling method is this?

Accepted Answer

Stratified sampling

Question 12

Which of the following best describes the placebo effect?

Accepted Answer

When a subject receives a placebo and reports improvement in symptoms.

Question 13

Which of the following is NOT a probability sampling method?

Accepted Answer

Convenience sampling

Question 14

A researcher collects data by reviewing medical records from the past 10 years. What type of observational study is this?

Accepted Answer

Retrospective study

Question 15

Which of the following is a key feature of a randomized block design?

Accepted Answer

Subjects are grouped into blocks based on similar characteristics, then randomly assigned treatments within each block.

Question 16

Which of the following statements about sampling error is correct?

Accepted Answer

Sampling error is the discrepancy between a sample result and the true population result due to chance.

Question 17

A researcher uses a combination of stratified and cluster sampling in different stages of a survey. What is this approach called?

Accepted Answer

Multistage sampling

Question 18

Which of the following best describes an observational study?

Accepted Answer

Researchers observe and measure characteristics without modifying the subjects.

Question 19

A researcher selects a sample of college students by standing outside the library and asking the first 50 students who walk by to participate. What type of sampling is this?

Accepted Answer

Convenience sampling

Question 20

Which of the following is a real-world example of confounding?

Accepted Answer

A study finds that people who carry lighters are more likely to develop lung cancer, but fails to account for smoking.

Chapter 1: Introduction to Statistics - Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard