Question 1

Which of the following best describes a simple random sample?

Accepted Answer

A sample where every possible sample of the same size has an equal chance of being chosen.

Question 2

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

Accepted Answer

Double-blind experiment

Question 3

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

Accepted Answer

Temperature affecting both ice cream sales and drowning rates

Question 4

In which type of sampling is the population divided into groups (strata) that share similar characteristics, and then a sample is drawn from each group?

Accepted Answer

Stratified sampling

Question 5

A researcher selects every 10th person entering a hospital for a survey. What type of sampling is this?

Accepted Answer

Systematic sampling

Question 6

Which of the following best describes an observational study?

Accepted Answer

Researchers observe and measure characteristics without modifying the subjects.

Question 7

What is the main purpose of randomization in experimental design?

Accepted Answer

To create groups that are similar and reduce bias

Question 8

A study collects data from medical records of patients treated for heart disease over the past 10 years. What type of observational study is this?

Accepted Answer

Retrospective study

Question 9

Which of the following is a potential source of nonsampling error?

Accepted Answer

Entering incorrect data during analysis

Question 10

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

Accepted Answer

Cluster sampling

Question 11

Which of the following best describes confounding in an experiment?

Accepted Answer

When the experimenter cannot distinguish between the effects of different factors

Question 12

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 13

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

Accepted Answer

A discrepancy between a sample result and the true population result due to chance

Question 14

In a medical trial, patients are paired based on age and gender, and each pair is split so that one receives the treatment and the other receives a placebo. What experimental design is this?

Accepted Answer

Matched pairs design

Question 15

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

Accepted Answer

Convenience sampling

Question 16

A researcher collects data on students' study habits and grades at a single point in time. What type of observational study is this?

Accepted Answer

Cross-sectional study

Question 17

Which of the following best describes the placebo effect?

Accepted Answer

When an untreated subject reports improvement in symptoms

Question 18

A researcher selects a sample of college students by standing outside the library and asking the first 20 students who walk by. What type of sampling is this?

Accepted Answer

Convenience sampling

Question 19

Which of the following is a key reason why the method of data collection is important in statistics?

Accepted Answer

It influences the quality and validity of the statistical analysis.

Question 20

In a randomized block design, what is the main purpose of creating blocks?

Accepted Answer

To group subjects that are similar in ways that might affect the outcome

Introduction to Statistics: Collecting Data and Experimental Design

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