503 Population Health, Epidemiology &
Statistical Principles | Chamberlain
1. A researcher wants to determine the number of new cases of influenza in a specific
community over the course of the 2023 winter season. Which measure of frequency is being
used?
A. Prevalence
B. Attack Rate
C. Mortality Rate
D. Incidence
Answer: D
Rationale: Incidence refers to the number of new cases of a disease that develop in a
population at risk during a specified time period. It is essential for understanding the risk
of developing a condition and tracking the spread of infectious diseases. In contrast,
prevalence measures all existing cases at a single point in time regardless of when they
started.
2. When evaluating a new diagnostic test, the ability of the test to correctly identify those
who truly do not have the disease is known as:
A. Sensitivity
,B. Specificity
C. Positive Predictive Value
D. Negative Predictive Value
Answer: B
Rationale: Specificity is the proportion of people without the disease who receive a
negative test result. High specificity is crucial for minimizing false positives, which can lead
to unnecessary anxiety and further invasive testing. A test with 100% specificity will
correctly identify all healthy individuals.
3. In a study exploring the relationship between smoking and lung cancer, the researcher
compares a group of individuals with lung cancer to a group without lung cancer to look at
past smoking habits. This is an example of what type of study design?
A. Cohort Study
B. Cross-sectional Study
C. Case-Control Study
D. Randomized Controlled Trial
Answer: C
Rationale: A case-control study starts with the outcome (cases with disease and controls
without) and looks back in time to identify exposures. This design is particularly useful for
, studying rare diseases or conditions with long latency periods. It relies on the retrospective
collection of data, often through interviews or medical records.
4. Which level of prevention is focused on minimizing the impact of a permanent or
irreversible disease or injury?
A. Primary Prevention
B. Secondary Prevention
C. Quaternary Prevention
D. Tertiary Prevention
Answer: D
Rationale: Tertiary prevention aims to soften the impact of an ongoing illness or injury
that has lasting effects. This is done by helping people manage long-term, complex health
problems and injuries to improve as much as possible their ability to function. Examples
include cardiac rehabilitation or physical therapy after a stroke.
5. A p-value of 0.03 is obtained in a clinical trial comparing two medications. Assuming the
alpha level is set at 0.05, what should the researcher conclude?
A. The results are significant, and the null hypothesis is accepted.
B. The results are not statistically significant, and the null hypothesis is accepted.
C. The test lacks enough power to make a conclusion.
D. The results are statistically significant, and the null hypothesis is rejected.