Question 1

Which of the following best describes the main limitation of in vitro studies in nutrition research?

Accepted Answer

Their results cannot be directly applied to whole living organisms.

Question 2

A researcher wants to determine if a new dietary supplement causes a reduction in blood pressure. Which study design would provide the strongest evidence for causation?

Accepted Answer

Randomized controlled trial

Question 3

In a cohort study, what is the main reason it cannot prove causation?

Accepted Answer

It cannot control for all confounding factors.

Question 4

Which of the following is an example of a confounding factor in a study examining the relationship between dairy consumption and cancer risk?

Accepted Answer

Participants' physical activity levels

Question 5

A study exposes isolated human cells to a nutrient and measures changes in gene expression. What type of study is this?

Accepted Answer

In vitro study

Question 6

Which of the following best describes the placebo effect?

Accepted Answer

A beneficial effect due to a subject’s belief in the treatment, even if the treatment is inactive

Question 7

A systematic review combines the results of multiple studies to draw a conclusion. What is the statistical technique called when data from these studies are quantitatively combined?

Accepted Answer

Meta-analysis

Question 8

Which of the following is the correct order of the hierarchy of evidence, from lowest to highest?

Accepted Answer

In vitro and animal studies, observational studies, intervention studies, meta-analyses and systematic reviews

Question 9

A study follows a group of healthy individuals over 20 years, periodically measuring their diets and health outcomes. What type of study is this?

Accepted Answer

Cohort study

Question 10

Why is randomization important in intervention studies?

Accepted Answer

It helps ensure that groups are similar except for the intervention, reducing confounding factors.

Question 11

A published article analyzes the results of 49 previous studies on dietary nitrates and cancer risk. What type of publication is this?

Accepted Answer

Secondary source

Question 12

Which of the following is a key characteristic of high-quality scientific writing?

Accepted Answer

It proposes new studies to address unanswered questions.

Question 13

A study finds a positive correlation between cheese consumption and deaths from bedsheet tangling. What is the most appropriate interpretation?

Accepted Answer

There is a relationship, but no evidence of causation.

Question 14

Which of the following best describes a primary source in scientific research?

Accepted Answer

A journal article presenting original experimental data

Question 15

A nutrition researcher wants to study the effect of a new vitamin supplement on cholesterol levels. She recruits 100 participants, randomly assigns them to receive either the supplement or a placebo, and measures cholesterol after 6 months. What is the independent variable in this study?

Accepted Answer

Vitamin supplement or placebo

Question 16

Which of the following is a limitation of intervention studies in human nutrition?

Accepted Answer

They can be expensive and difficult to maintain compliance over long periods.

Question 17

A case-control study is most useful for which of the following scenarios?

Accepted Answer

Studying rare diseases by comparing those with the disease to similar people without it

Question 18

Which of the following best distinguishes correlation from causation?

Accepted Answer

Causation means one variable directly produces a change in another.

Question 19

A study collects dietary recall data from participants and compares it to their health outcomes. What is a major challenge with this method?

Accepted Answer

Participants may under-report or misremember their intake.

Question 20

Which of the following is NOT a hallmark of a good study design?

Accepted Answer

The independent and dependent variables are changed simultaneously.

Study Types, Evidence Hierarchy, and Research Interpretation in Nutrition

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