Question 1

Which of the following best describes a confounding variable in a study examining the relationship between ice cream sales and beach attendance?

Accepted Answer

A variable that is not accounted for but influences both ice cream sales and beach attendance, such as temperature.

Question 2

In a controlled experiment, which practice helps minimize bias between treatment and control groups?

Accepted Answer

Randomly assigning subjects to groups using technology.

Question 3

A study investigates whether a new medication reduces blood pressure. Participants are randomly assigned to receive either the medication or a placebo. Neither the participants nor the researchers know who receives which treatment. What is this study design called?

Accepted Answer

Double-blind controlled experiment

Question 4

Which of the following is NOT a characteristic of the 'gold standard' in experimental design?

Accepted Answer

Subjects choose their own group

Question 5

A researcher wants to study the effect of a diet aid. She records whether participants take the aid and whether they lose weight. Which variable is the treatment variable?

Accepted Answer

Whether participants take the diet aid

Question 6

In an observational study, which of the following statements is TRUE?

Accepted Answer

Subjects are placed in groups by their own actions or by someone not involved in the study.

Question 7

Anecdotal evidence is considered weak in scientific studies because:

Accepted Answer

It relies on stories from individuals rather than systematic data collection.

Question 8

Which of the following best illustrates the placebo effect?

Accepted Answer

A patient feels better after receiving a sugar pill, believing it is real medicine.

Question 9

A study finds that people who exercise regularly have lower cholesterol. However, the study did not control for diet. What is diet in this context?

Accepted Answer

A confounding variable

Question 10

Which equation best represents the probability of randomly assigning a subject to the treatment group in a study with $$n$$ subjects and $$k$$ treatment spots?

Accepted Answer

$$P = \frac{k}{n}$$

Question 11

A news article reports a study showing a link between drinking coffee and reduced risk of heart disease. Which question should you ask to evaluate the study's reliability?

Accepted Answer

Was the study published in a peer-reviewed journal?

Question 12

In a double-blind experiment, who knows which subjects are in the treatment group?

Accepted Answer

Neither the researchers nor the subjects

Question 13

Which scenario best demonstrates an association but not causation?

Accepted Answer

Observing that ice cream sales increase when more people go to the beach.

Question 14

A researcher assigns children to watch either a fast-paced cartoon or read a book, then measures their attention span. What type of study is this?

Accepted Answer

Controlled experiment

Question 15

Which of the following is a key advantage of random assignment in experiments?

Accepted Answer

It balances out differences between groups, minimizing bias.

Question 16

If a study uses a placebo, what is the main purpose?

Accepted Answer

To control for psychological effects unrelated to the actual treatment.

Question 17

Which formula would you use to calculate the proportion of subjects in the treatment group if there are $$n$$ total subjects and $$t in $$the treatment group?

Accepted Answer

$$p = \frac{t}{n}$$

Question 18

Which of the following best describes the outcome variable in a study testing a new drug for headaches?

Accepted Answer

Whether participants report relief from headaches

Question 19

A study follows participants for 10 years to observe the effects of a new exercise program on heart health. Which aspect of the 'gold standard' does this best illustrate?

Accepted Answer

Long-term follow-up

Question 20

Which of the following is most likely to establish causality?

Accepted Answer

A controlled experiment with random assignment and double-blinding

Collecting Data to Understand Causality: Experimental and Observational Studies

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