NR503 Exam 3 Actual Exam Style V1 | NR
503 Population Health, Epidemiology &
Statistical Principles | Chamberlain
1. Which of the following terms describes the ability of a screening test to correctly identify
those who do not have the disease?
A. Specificity
B. Sensitivity
C. Positive Predictive Value
D. Negative Predictive Value
Answer: A
Rationale: Specificity measures the proportion of individuals without the disease who are
correctly identified by the test. It is essential for minimizing false positives in a population.
High specificity ensures that healthy people are not subjected to unnecessary follow-up
procedures.
2. When a screening program detects a disease earlier than it would have been diagnosed
symptoms appeared, but the time of death is not changed, what type of bias occurs?
A. Length-time bias
B. Lead-time bias
C. Selection bias
,D. Information bias
Answer: B
Rationale: Lead-time bias occurs when the survival time appears longer simply because
the disease was caught earlier. It does not actually reflect an extension of life through
treatment efficacy. Researchers must account for this to avoid overestimating the benefits
of screening.
3. In a cohort study, the primary measure used to determine the association between an
exposure and an outcome is:
A. Relative Risk
B. Odds Ratio
C. Prevalence Rate
D. Sensitivity
Answer: A
Rationale: Relative risk compares the incidence of disease in an exposed group to the
incidence in an unexposed group. It is the standard measure of association for longitudinal
cohort studies. This metric helps clinicians understand how much the risk increases with a
specific exposure.
4. A study compares the rates of lung cancer in different countries with the average national
tobacco consumption. This is an example of which study design?
A. Case-control study
, B. Randomized controlled trial
C. Cohort study
D. Ecological study
Answer: D
Rationale: Ecological studies analyze data at the population or group level rather than the
individual level. They are useful for generating hypotheses but are subject to the ecological
fallacy. This design is often used when individual data is unavailable or difficult to obtain.
5. Which ethical principle from the Belmont Report emphasizes that the benefits and burdens
of research should be distributed fairly?
A. Beneficence
B. Justice
C. Respect for Persons
D. Non-maleficence
Answer: B
Rationale: The principle of Justice requires that the selection of research participants is
equitable. It prevents vulnerable populations from being exploited while ensuring all
groups have access to research benefits. This principle is foundational to modern ethical
review boards.
503 Population Health, Epidemiology &
Statistical Principles | Chamberlain
1. Which of the following terms describes the ability of a screening test to correctly identify
those who do not have the disease?
A. Specificity
B. Sensitivity
C. Positive Predictive Value
D. Negative Predictive Value
Answer: A
Rationale: Specificity measures the proportion of individuals without the disease who are
correctly identified by the test. It is essential for minimizing false positives in a population.
High specificity ensures that healthy people are not subjected to unnecessary follow-up
procedures.
2. When a screening program detects a disease earlier than it would have been diagnosed
symptoms appeared, but the time of death is not changed, what type of bias occurs?
A. Length-time bias
B. Lead-time bias
C. Selection bias
,D. Information bias
Answer: B
Rationale: Lead-time bias occurs when the survival time appears longer simply because
the disease was caught earlier. It does not actually reflect an extension of life through
treatment efficacy. Researchers must account for this to avoid overestimating the benefits
of screening.
3. In a cohort study, the primary measure used to determine the association between an
exposure and an outcome is:
A. Relative Risk
B. Odds Ratio
C. Prevalence Rate
D. Sensitivity
Answer: A
Rationale: Relative risk compares the incidence of disease in an exposed group to the
incidence in an unexposed group. It is the standard measure of association for longitudinal
cohort studies. This metric helps clinicians understand how much the risk increases with a
specific exposure.
4. A study compares the rates of lung cancer in different countries with the average national
tobacco consumption. This is an example of which study design?
A. Case-control study
, B. Randomized controlled trial
C. Cohort study
D. Ecological study
Answer: D
Rationale: Ecological studies analyze data at the population or group level rather than the
individual level. They are useful for generating hypotheses but are subject to the ecological
fallacy. This design is often used when individual data is unavailable or difficult to obtain.
5. Which ethical principle from the Belmont Report emphasizes that the benefits and burdens
of research should be distributed fairly?
A. Beneficence
B. Justice
C. Respect for Persons
D. Non-maleficence
Answer: B
Rationale: The principle of Justice requires that the selection of research participants is
equitable. It prevents vulnerable populations from being exploited while ensuring all
groups have access to research benefits. This principle is foundational to modern ethical
review boards.
