NR503 Exam 4 Actual Exam Style V1 | NR
503 Population Health, Epidemiology &
Statistical Principles | Chamberlain
1. Which measure of disease frequency specifically identifies the number of new cases
occurring in a population over a specific period?
A. Prevalence
B. Incidence
C. Attack Rate
D. Morbidity Rate
Answer: B
Rationale: Incidence refers to the number of new cases of a disease that develop in a
population during a defined timeframe. It is often used to assess the risk of developing a
condition within that population. This differs from prevalence, which counts both new and
existing cases at a single point in time.
2. In a study comparing smokers to non-smokers, the risk of lung cancer was significantly
higher in smokers. This type of prospective study is known as:
A. Case-control study
B. Cross-sectional study
C. Cohort study
,D. Ecological study
Answer: C
Rationale: A cohort study follows a group of people over time to see how different
exposures affect their outcomes. It starts with individuals who are free of the outcome and
classifies them based on their exposure status. This design is excellent for determining the
temporal relationship between exposure and disease.
3. Sensitivity in a diagnostic test refers to which of the following?
A. The proportion of positive tests that are actually true positives
B. The ability of a test to correctly identify those without the disease
C. The ability of a test to correctly identify those with the disease
D. The likelihood that a negative test is a true negative
Answer: C
Rationale: Sensitivity measures the proportion of actual positives that are correctly
identified by the test. A highly sensitive test is useful for screening because it minimizes
false negatives. If a test has high sensitivity, a negative result helps rule out the disease with
confidence.
4. Which statistical value represents the probability that the observed results occurred by
chance alone?
A. P-value
, B. Odds Ratio
C. Confidence Interval
D. Relative Risk
Answer: A
Rationale: The p-value is used in hypothesis testing to determine the significance of the
results. A low p-value, typically less than 0.05, suggests that the null hypothesis should be
rejected. It indicates that the observed association is unlikely to be due to random
variation.
5. A researcher wants to study a rare disease. Which study design is most efficient for this
purpose?
A. Randomized Controlled Trial
B. Cohort Study
C. Community Trial
D. Case-control Study
Answer: D
Rationale: Case-control studies are ideal for investigating rare diseases because they start
with people who already have the outcome. Researchers then look backward in time to
identify previous exposures or characteristics. This design is more cost-effective and faster
than following a cohort for many years to see if a rare disease develops.
503 Population Health, Epidemiology &
Statistical Principles | Chamberlain
1. Which measure of disease frequency specifically identifies the number of new cases
occurring in a population over a specific period?
A. Prevalence
B. Incidence
C. Attack Rate
D. Morbidity Rate
Answer: B
Rationale: Incidence refers to the number of new cases of a disease that develop in a
population during a defined timeframe. It is often used to assess the risk of developing a
condition within that population. This differs from prevalence, which counts both new and
existing cases at a single point in time.
2. In a study comparing smokers to non-smokers, the risk of lung cancer was significantly
higher in smokers. This type of prospective study is known as:
A. Case-control study
B. Cross-sectional study
C. Cohort study
,D. Ecological study
Answer: C
Rationale: A cohort study follows a group of people over time to see how different
exposures affect their outcomes. It starts with individuals who are free of the outcome and
classifies them based on their exposure status. This design is excellent for determining the
temporal relationship between exposure and disease.
3. Sensitivity in a diagnostic test refers to which of the following?
A. The proportion of positive tests that are actually true positives
B. The ability of a test to correctly identify those without the disease
C. The ability of a test to correctly identify those with the disease
D. The likelihood that a negative test is a true negative
Answer: C
Rationale: Sensitivity measures the proportion of actual positives that are correctly
identified by the test. A highly sensitive test is useful for screening because it minimizes
false negatives. If a test has high sensitivity, a negative result helps rule out the disease with
confidence.
4. Which statistical value represents the probability that the observed results occurred by
chance alone?
A. P-value
, B. Odds Ratio
C. Confidence Interval
D. Relative Risk
Answer: A
Rationale: The p-value is used in hypothesis testing to determine the significance of the
results. A low p-value, typically less than 0.05, suggests that the null hypothesis should be
rejected. It indicates that the observed association is unlikely to be due to random
variation.
5. A researcher wants to study a rare disease. Which study design is most efficient for this
purpose?
A. Randomized Controlled Trial
B. Cohort Study
C. Community Trial
D. Case-control Study
Answer: D
Rationale: Case-control studies are ideal for investigating rare diseases because they start
with people who already have the outcome. Researchers then look backward in time to
identify previous exposures or characteristics. This design is more cost-effective and faster
than following a cohort for many years to see if a rare disease develops.
