Q: Which equation best represents the calculation of a knowledge-gained score in a pre- and post-test matched-pairs design?

$$\text{Knowledge-gained score} = \text{Post-test score} - \text{Pre-test score}$$

Question 1

In a study investigating whether daily coffee consumption reduces the risk of nonmelanoma skin cancer, which of the following is the explanatory variable?

Accepted Answer

Daily coffee consumption

Question 2

Which of the following best describes a designed experiment?

Accepted Answer

Researchers apply a treatment to subjects and observe the effects.

Question 3

A pharmaceutical company randomly assigns 300 adult males with colds into two groups: one receives a new drug, the other a placebo. After one week, the proportion still with symptoms is compared. What type of experimental design is this?

Accepted Answer

Completely randomized design

Question 4

Which of the following statements about confounding is TRUE?

Accepted Answer

Confounding can falsely suggest a causal relationship when none exists.

Question 5

In a matched-pairs before-and-after design, what is the main advantage?

Accepted Answer

Each subject serves as their own control, reducing variability.

Question 6

Which of the following is a characteristic of a double-blind experiment?

Accepted Answer

Neither the subject nor the researcher knows which treatment is given.

Question 7

A study asks 400 people whether they prefer Coke or Pepsi. What type of study is this?

Accepted Answer

Observational study

Question 8

Which of the following best describes a cohort study?

Accepted Answer

It follows a group of individuals into the future to record outcomes.

Question 9

In the context of experimental design, what is a placebo?

Accepted Answer

An innocuous substance designed to look like the experimental treatment

Question 10

Which of the following is an example of a case-control study?

Accepted Answer

Comparing people with lung cancer to those without and looking back at their smoking history

Question 11

Which equation best represents the calculation of a knowledge-gained score in a pre- and post-test matched-pairs design?

Accepted Answer

$$	ext{Knowledge-gained score} = 	ext{Post-test score} - 	ext{Pre-test score}$$

Question 12

Which of the following is NOT a type of observational study?

Accepted Answer

Completely randomized design

Question 13

A researcher wants to determine if sunscreen use causes skin cancer but is concerned about confounding. Which variable is most likely a confounder in this scenario?

Accepted Answer

Sun exposure

Question 14

In a completely randomized design, how are experimental units assigned to treatments?

Accepted Answer

Randomly and independently

Question 15

Which of the following best describes the response variable in an experiment?

Accepted Answer

The outcome that is measured on each experimental unit

Question 16

A study divides rats with cancer into two groups, giving one group 5 mg of a medication and the other 10 mg, then measures cancer spread after 2 years. What type of study is this?

Accepted Answer

Designed experiment

Question 17

Which of the following is a key reason why observational studies cannot establish causation?

Accepted Answer

They cannot control for confounding variables

Question 18

In a matched-pairs parallel design, how are subjects assigned to groups?

Accepted Answer

Pairs of subjects with similar characteristics are formed, and each member of the pair is randomly assigned to a different group

Question 19

Which of the following best describes a cross-sectional study?

Accepted Answer

It collects data from individuals at a specific point in time

Question 20

A researcher wants to compare the effectiveness of two teaching methods. She gives students a pre-test, teaches them using one method, then gives a post-test. What is the response variable?

Accepted Answer

The difference between post-test and pre-test scores

Observation, Experimentation, and Experimental Design in Statistics

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