Question 1

Which of the following best describes an observational study?

Accepted Answer

A researcher observes and measures characteristics of interest without influencing the subjects.

Question 2

A pharmaceutical company wants to test a new drug. They divide 200 patients into two groups: one receives the drug, and the other receives a placebo. Neither the patients nor the doctors know who receives the drug. What type of experimental design is this?

Accepted Answer

Double-blind experiment

Question 3

Which of the following is a key element of a well-designed experiment?

Accepted Answer

Replication

Question 4

A researcher wants to study the effect of a new teaching method. She randomly assigns students to two groups, ensuring each group is similar in age and prior achievement. What sampling technique is being used?

Accepted Answer

Stratified sampling

Question 5

Which of the following scenarios best illustrates a confounding variable?

Accepted Answer

A coffee shop remodels at the same time a new mall opens, making it unclear which event increased business.

Question 6

What is the main purpose of using a placebo in an experiment?

Accepted Answer

To minimize the placebo effect by blinding subjects to their group assignment

Question 7

A researcher selects every 10th person from a list of 1,000 employees. What type of sampling is this?

Accepted Answer

Systematic sampling

Question 8

Which of the following best describes a census?

Accepted Answer

A count or measure of an entire population

Question 9

A study is conducted to determine the average commute time for all students at a university. The researcher surveys only students in her statistics class. What is the main issue with this sampling method?

Accepted Answer

It is a convenience sample and may be biased

Question 10

Which of the following is an example of replication in experimental design?

Accepted Answer

Repeating an experiment with a large group of subjects to confirm results

Question 11

A researcher uses a computer model to study the effects of a new car design on crash safety. What type of data collection method is this?

Accepted Answer

Simulation

Question 12

Which of the following statements about simple random sampling is correct?

Accepted Answer

Every possible sample of the same size has the same chance of being selected.

Question 13

A researcher divides a city into neighborhoods and randomly selects several neighborhoods. All residents in those neighborhoods are surveyed. What sampling technique is this?

Accepted Answer

Cluster sampling

Question 14

Which of the following is a potential source of bias in survey design?

Accepted Answer

Wording questions in a way that leads to a particular response

Question 15

A researcher pairs subjects based on age and randomly assigns one from each pair to receive a treatment. What experimental design is this?

Accepted Answer

Matched-pairs design

Question 16

Which of the following best describes a sampling error?

Accepted Answer

The difference between the results of a sample and those of the population

Question 17

A researcher divides a population into socioeconomic levels and randomly selects households from each level. What sampling technique is this?

Accepted Answer

Stratified sampling

Question 18

Which of the following is NOT a key element of a well-designed experiment?

Accepted Answer

Convenience

Question 19

A study is conducted to determine how confident Americans are in the economy by calling 3,040 adults and asking them to rate current conditions. What type of study is this?

Accepted Answer

Observational study

Question 20

Which of the following best describes the process of randomization in experimental design?

Accepted Answer

Randomly assigning subjects to different treatment groups to reduce bias

Introduction to Statistics: Data Collection and Experimental Design

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