NR 503 EPIDEMIOLOGY FINAL EXAM 2026 ACTUAL
EXAM QUESTIONS AND CORRECT DETAILED
ANSWERS WITH RATIONALES LATEST VERSION
(VERIFIED ANSWERS) ALREADY GRADED A+
1. A nurse practitioner is reviewing surveillance data and notes that there were 250 new cases
of influenza diagnosed in a city of 50,000 people during the month of January. Which
epidemiologic measure is being described?
A. Prevalence
B. Mortality rate
C. Attack rate
D. Incidence
Answer: D
Rationale: Incidence measures the number of new cases of a disease occurring in a defined
population during a specified period. It is used to estimate the risk of developing a disease
and is especially useful in identifying emerging diseases and evaluating preventive
interventions.
2. Which epidemiologic measure represents the total number of existing cases of a disease in
a population at a specific point in time?
A. Incidence
B. Relative Risk
C. Case Fatality Rate
D. Prevalence
,Answer: D
Rationale: Prevalence includes both new and existing cases of disease at a particular point or
period in time. It reflects the overall disease burden within a population and is commonly
used for planning healthcare services.
3. A researcher wants to determine whether cigarette smoking increases the risk of
developing lung cancer by following healthy individuals over 20 years. Which study design is
MOST appropriate?
A. Cross-sectional study
B. Case-control study
C. Ecological study
D. Prospective cohort study
Answer: D
Rationale: A prospective cohort study follows disease-free individuals over time to determine
whether exposure to a risk factor results in disease. This design allows calculation of
incidence and relative risk while establishing the temporal relationship between exposure and
disease.
4. Which epidemiologic study design is BEST suited for investigating a rare disease?
A. Cohort study
B. Cross-sectional study
C. Randomized controlled trial
D. Case-control study
Answer: D
Rationale: Case-control studies begin with individuals who already have the disease (cases)
and compare them with those who do not (controls). They are efficient, cost-effective, and
especially useful for studying rare diseases or diseases with long latency periods.
5. Which level of prevention focuses on preventing disease before it occurs through health
promotion and risk reduction?
A. Secondary prevention
B. Tertiary prevention
,C. Quaternary prevention
D. Primary prevention
Answer: D
Rationale: Primary prevention aims to prevent disease before it develops through
interventions such as immunizations, smoking cessation, healthy nutrition, physical activity,
and health education.
6. Which intervention is an example of secondary prevention?
A. Smoking cessation counseling
B. Physical activity promotion
C. Rehabilitation after stroke
D. Screening mammography to detect breast cancer early
Answer: D
Rationale: Secondary prevention focuses on early detection and treatment of disease before
symptoms become severe. Examples include mammography, colonoscopy, blood pressure
screening, and diabetes screening.
7. Which intervention is considered tertiary prevention?
A. Childhood immunizations
B. Seat belt education
C. Blood pressure screening
D. Cardiac rehabilitation following myocardial infarction
Answer: D
Rationale: Tertiary prevention aims to reduce disability, improve function, and prevent
complications after disease has occurred. Rehabilitation programs, chronic disease
management, and physical therapy are common examples.
8. A screening test has a high sensitivity. What does this indicate?
A. It correctly identifies individuals without disease.
B. It has very few false-positive results.
C. It confirms disease with certainty.
, D. It correctly identifies most individuals who have the disease.
Answer: D
Rationale: Highly sensitive tests produce very few false negatives, making them useful for
screening because they identify nearly everyone who truly has the disease.
9. A diagnostic test has high specificity. Which statement is TRUE?
A. It produces many false-positive results.
B. It identifies everyone with disease.
C. It has low accuracy.
D. It correctly identifies individuals who do not have the disease.
Answer: D
Rationale: Highly specific tests produce very few false-positive results and are useful for
confirming a diagnosis after an initial positive screening test.
10. What is the Positive Predictive Value (PPV) of a screening test?
A. The probability that a negative result is truly disease-free.
B. The percentage of healthy individuals correctly identified.
C. The proportion of false-positive results.
D. The probability that a person with a positive test truly has the disease.
Answer: D
Rationale: Positive Predictive Value indicates the likelihood that an individual with a positive
screening result actually has the disease. PPV increases as disease prevalence increases.
11. Which epidemiologic measure is MOST useful for determining the probability that an
exposed individual will develop disease compared with an unexposed individual?
A. Odds Ratio
B. Prevalence Ratio
C. Attributable Risk
D. Relative Risk (Risk Ratio)
Answer: D
EXAM QUESTIONS AND CORRECT DETAILED
ANSWERS WITH RATIONALES LATEST VERSION
(VERIFIED ANSWERS) ALREADY GRADED A+
1. A nurse practitioner is reviewing surveillance data and notes that there were 250 new cases
of influenza diagnosed in a city of 50,000 people during the month of January. Which
epidemiologic measure is being described?
A. Prevalence
B. Mortality rate
C. Attack rate
D. Incidence
Answer: D
Rationale: Incidence measures the number of new cases of a disease occurring in a defined
population during a specified period. It is used to estimate the risk of developing a disease
and is especially useful in identifying emerging diseases and evaluating preventive
interventions.
2. Which epidemiologic measure represents the total number of existing cases of a disease in
a population at a specific point in time?
A. Incidence
B. Relative Risk
C. Case Fatality Rate
D. Prevalence
,Answer: D
Rationale: Prevalence includes both new and existing cases of disease at a particular point or
period in time. It reflects the overall disease burden within a population and is commonly
used for planning healthcare services.
3. A researcher wants to determine whether cigarette smoking increases the risk of
developing lung cancer by following healthy individuals over 20 years. Which study design is
MOST appropriate?
A. Cross-sectional study
B. Case-control study
C. Ecological study
D. Prospective cohort study
Answer: D
Rationale: A prospective cohort study follows disease-free individuals over time to determine
whether exposure to a risk factor results in disease. This design allows calculation of
incidence and relative risk while establishing the temporal relationship between exposure and
disease.
4. Which epidemiologic study design is BEST suited for investigating a rare disease?
A. Cohort study
B. Cross-sectional study
C. Randomized controlled trial
D. Case-control study
Answer: D
Rationale: Case-control studies begin with individuals who already have the disease (cases)
and compare them with those who do not (controls). They are efficient, cost-effective, and
especially useful for studying rare diseases or diseases with long latency periods.
5. Which level of prevention focuses on preventing disease before it occurs through health
promotion and risk reduction?
A. Secondary prevention
B. Tertiary prevention
,C. Quaternary prevention
D. Primary prevention
Answer: D
Rationale: Primary prevention aims to prevent disease before it develops through
interventions such as immunizations, smoking cessation, healthy nutrition, physical activity,
and health education.
6. Which intervention is an example of secondary prevention?
A. Smoking cessation counseling
B. Physical activity promotion
C. Rehabilitation after stroke
D. Screening mammography to detect breast cancer early
Answer: D
Rationale: Secondary prevention focuses on early detection and treatment of disease before
symptoms become severe. Examples include mammography, colonoscopy, blood pressure
screening, and diabetes screening.
7. Which intervention is considered tertiary prevention?
A. Childhood immunizations
B. Seat belt education
C. Blood pressure screening
D. Cardiac rehabilitation following myocardial infarction
Answer: D
Rationale: Tertiary prevention aims to reduce disability, improve function, and prevent
complications after disease has occurred. Rehabilitation programs, chronic disease
management, and physical therapy are common examples.
8. A screening test has a high sensitivity. What does this indicate?
A. It correctly identifies individuals without disease.
B. It has very few false-positive results.
C. It confirms disease with certainty.
, D. It correctly identifies most individuals who have the disease.
Answer: D
Rationale: Highly sensitive tests produce very few false negatives, making them useful for
screening because they identify nearly everyone who truly has the disease.
9. A diagnostic test has high specificity. Which statement is TRUE?
A. It produces many false-positive results.
B. It identifies everyone with disease.
C. It has low accuracy.
D. It correctly identifies individuals who do not have the disease.
Answer: D
Rationale: Highly specific tests produce very few false-positive results and are useful for
confirming a diagnosis after an initial positive screening test.
10. What is the Positive Predictive Value (PPV) of a screening test?
A. The probability that a negative result is truly disease-free.
B. The percentage of healthy individuals correctly identified.
C. The proportion of false-positive results.
D. The probability that a person with a positive test truly has the disease.
Answer: D
Rationale: Positive Predictive Value indicates the likelihood that an individual with a positive
screening result actually has the disease. PPV increases as disease prevalence increases.
11. Which epidemiologic measure is MOST useful for determining the probability that an
exposed individual will develop disease compared with an unexposed individual?
A. Odds Ratio
B. Prevalence Ratio
C. Attributable Risk
D. Relative Risk (Risk Ratio)
Answer: D
