NR 503 EPIDEMIOLOGY MIDTERM EXAM –
CHAMBERLAIN COLLEGE OF NURSING ||
2025/2026 COMPLETE QUESTIONS &
CORRECT DETAILED ANSWERS ||
GUARANTEED PASS <UPDATED>
Practice Midterm Questions – Epidemiology (Rewritten Version)
Q1. What does the field of epidemiology focus on?
Answer:
Epidemiology examines how health conditions are distributed in populations, the factors that
influence them, and applies this knowledge to prevent and control health problems.
Q2. How do incidence and prevalence differ?
Answer:
• Incidence: Refers to the number of newly diagnosed cases of a disease during a
specific period.
• Prevalence: Refers to the total number of existing cases (new and old) in a population
at a given point in time.
Q3. What is the distinction between descriptive and analytic epidemiology?
Answer:
• Descriptive epidemiology: Outlines patterns of disease in terms of person, place, and
time.
• Analytic epidemiology: Explores the causal relationships by asking why and how
diseases occur.
, Q4. Define a cohort study and its purpose.
Answer:
A cohort study follows groups of people with differing exposures over time to measure the
occurrence of outcomes, making it useful for evaluating incidence and risk factors.
Q5. What is meant by herd immunity?
Answer:
Herd immunity occurs when enough of a population is immune to an infectious disease (via
vaccination or prior illness), thereby protecting those who are not immune by limiting disease
spread.
Q6. If 80 students attend a school event and 16 report illness afterward, what is the attack
rate?
Answer:
Attack rate = (Number of people sick ÷ Total exposed) × 100
= (16 ÷ 80) × 100 = 20%
Q7. Explain sensitivity and specificity in diagnostic testing.
Answer:
• Sensitivity: The test’s ability to correctly detect individuals with the disease (true
positives).
• Specificity: The test’s ability to correctly identify individuals without the disease (true
negatives).
Q8. Define endemic, epidemic, and pandemic with examples.
Answer:
• Endemic: Constant presence of a disease within a population (e.g., chickenpox in some
regions).
• Epidemic: A sudden rise in disease cases above what is normally expected.
• Pandemic: A global outbreak affecting multiple countries or continents (e.g., COVID-
19).
CHAMBERLAIN COLLEGE OF NURSING ||
2025/2026 COMPLETE QUESTIONS &
CORRECT DETAILED ANSWERS ||
GUARANTEED PASS <UPDATED>
Practice Midterm Questions – Epidemiology (Rewritten Version)
Q1. What does the field of epidemiology focus on?
Answer:
Epidemiology examines how health conditions are distributed in populations, the factors that
influence them, and applies this knowledge to prevent and control health problems.
Q2. How do incidence and prevalence differ?
Answer:
• Incidence: Refers to the number of newly diagnosed cases of a disease during a
specific period.
• Prevalence: Refers to the total number of existing cases (new and old) in a population
at a given point in time.
Q3. What is the distinction between descriptive and analytic epidemiology?
Answer:
• Descriptive epidemiology: Outlines patterns of disease in terms of person, place, and
time.
• Analytic epidemiology: Explores the causal relationships by asking why and how
diseases occur.
, Q4. Define a cohort study and its purpose.
Answer:
A cohort study follows groups of people with differing exposures over time to measure the
occurrence of outcomes, making it useful for evaluating incidence and risk factors.
Q5. What is meant by herd immunity?
Answer:
Herd immunity occurs when enough of a population is immune to an infectious disease (via
vaccination or prior illness), thereby protecting those who are not immune by limiting disease
spread.
Q6. If 80 students attend a school event and 16 report illness afterward, what is the attack
rate?
Answer:
Attack rate = (Number of people sick ÷ Total exposed) × 100
= (16 ÷ 80) × 100 = 20%
Q7. Explain sensitivity and specificity in diagnostic testing.
Answer:
• Sensitivity: The test’s ability to correctly detect individuals with the disease (true
positives).
• Specificity: The test’s ability to correctly identify individuals without the disease (true
negatives).
Q8. Define endemic, epidemic, and pandemic with examples.
Answer:
• Endemic: Constant presence of a disease within a population (e.g., chickenpox in some
regions).
• Epidemic: A sudden rise in disease cases above what is normally expected.
• Pandemic: A global outbreak affecting multiple countries or continents (e.g., COVID-
19).
