1
NR 503 WEEK 8 FINAL QUIZ 2026/2027 | Population
Health & Epidemiology | 100% Correct Exam
Elaborations | Pass Guaranteed - A+ Graded
[Section 1: Epidemiology Foundations & Study Design (Q1-12)]
Q1. Which of the following BEST describes the difference between descriptive and
analytic epidemiology? A. Descriptive epidemiology focuses on individual patient
outcomes; analytic epidemiology focuses on population-level trends B. Descriptive
epidemiology characterizes disease distribution by person, place, and time; analytic
epidemiology tests hypotheses about determinants of disease C. Descriptive
epidemiology uses only cross-sectional studies; analytic epidemiology uses only
cohort studies D. Descriptive epidemiology requires control groups; analytic
epidemiology does not require control groups
B. Descriptive epidemiology characterizes disease distribution by person, place, and
time; analytic epidemiology tests hypotheses about determinants of disease
[CORRECT]
Rationale: Descriptive epidemiology answers "what, who, where, and when"
questions using data on person (age, sex, race), place (geography), and time
(seasonality, trends). Analytic epidemiology answers "why and how" questions by
testing hypotheses about associations between exposures and outcomes through
comparative study designs. Descriptive studies do not require control groups;
analytic studies do. Correct Answer: B
Q2. A researcher observes that countries with higher per capita chocolate
consumption have higher rates of Nobel laureates per capita. The researcher
concludes that chocolate consumption causes Nobel Prize winning. This conclusion is
flawed because of: A. Selection bias B. Ecological fallacy C. Confounding by indication
D. Recall bias
B. Ecological fallacy [CORRECT]
,2
Rationale: The ecological fallacy occurs when group-level associations are incorrectly
applied to individuals. Country-level data on chocolate consumption and Nobel
laureates cannot establish individual-level causation because the exposure and
outcome were not measured in the same individuals. Wealth, education
infrastructure, and research funding (confounders) likely explain both variables at the
country level. Correct Answer: B
Q3. A study examines the prevalence of hypertension among adults aged 18-65 in a
single community health fair during one weekend. Which study design is this? A.
Case-control study B. Cohort study C. Cross-sectional study D. Randomized
controlled trial
C. Cross-sectional study [CORRECT]
Rationale: A cross-sectional study measures exposure and outcome simultaneously at
a single point in time (or brief period), providing a "snapshot" of disease prevalence
and exposure distribution. This design cannot establish temporal sequence (which
came first) and is therefore limited for causal inference. It is useful for generating
hypotheses and planning health services. Correct Answer: C
Q4. A researcher identifies 200 women with breast cancer and 400 women without
breast cancer, then retrospectively assesses their lifetime oral contraceptive use.
Which study design is this? A. Prospective cohort study B. Retrospective cohort study
C. Case-control study D. Ecological study
C. Case-control study [CORRECT]
Rationale: A case-control study begins with the outcome (disease status: cases with
breast cancer, controls without) and looks backward in time to compare exposure
history (oral contraceptive use). This design is efficient for rare diseases and requires
fewer subjects than cohort studies, but is susceptible to recall bias and selection bias
in control recruitment. Correct Answer: C
, 3
Q5. Which of the following is the PRIMARY advantage of a randomized controlled
trial (RCT) over an observational cohort study? A. RCTs can study rare diseases more
efficiently B. RCTs eliminate confounding through randomization, creating
comparable groups C. RCTs require smaller sample sizes to achieve the same power
D. RCTs can measure incidence rates more accurately
B. RCTs eliminate confounding through randomization, creating comparable groups
[CORRECT]
Rationale: Randomization distributes both known and unknown confounders evenly
between intervention and control groups, minimizing confounding bias and
strengthening causal inference. This is the fundamental advantage of RCTs. However,
RCTs are often expensive, have limited generalizability, and may be unethical for
harmful exposures. They do not necessarily require smaller samples or study rare
diseases more efficiently. Correct Answer: B
Q6. In a cohort study of 1,000 smokers and 1,000 non-smokers followed for 10 years,
150 smokers and 30 non-smokers developed lung cancer. What is the relative risk
(RR)? A. 2.0 B. 3.0 C. 5.0 D. 7.5
C. 5.0 [CORRECT]
Rationale: RR = Incidence in exposed / Incidence in unexposed = (150/1000) /
(30/1000) = 0..03 = 5.0. This means smokers have 5 times the risk of lung
cancer compared to non-smokers. The RR is appropriate for cohort studies where
incidence can be calculated because subjects are followed over time. Correct Answer:
C
Q7. In the same smoking study (Q6), what is the attributable risk (AR) in the exposed
group? A. 3 per 100 B. 12 per 100 C. 15 per 100 D. 80 per 100
B. 12 per 100 [CORRECT]
NR 503 WEEK 8 FINAL QUIZ 2026/2027 | Population
Health & Epidemiology | 100% Correct Exam
Elaborations | Pass Guaranteed - A+ Graded
[Section 1: Epidemiology Foundations & Study Design (Q1-12)]
Q1. Which of the following BEST describes the difference between descriptive and
analytic epidemiology? A. Descriptive epidemiology focuses on individual patient
outcomes; analytic epidemiology focuses on population-level trends B. Descriptive
epidemiology characterizes disease distribution by person, place, and time; analytic
epidemiology tests hypotheses about determinants of disease C. Descriptive
epidemiology uses only cross-sectional studies; analytic epidemiology uses only
cohort studies D. Descriptive epidemiology requires control groups; analytic
epidemiology does not require control groups
B. Descriptive epidemiology characterizes disease distribution by person, place, and
time; analytic epidemiology tests hypotheses about determinants of disease
[CORRECT]
Rationale: Descriptive epidemiology answers "what, who, where, and when"
questions using data on person (age, sex, race), place (geography), and time
(seasonality, trends). Analytic epidemiology answers "why and how" questions by
testing hypotheses about associations between exposures and outcomes through
comparative study designs. Descriptive studies do not require control groups;
analytic studies do. Correct Answer: B
Q2. A researcher observes that countries with higher per capita chocolate
consumption have higher rates of Nobel laureates per capita. The researcher
concludes that chocolate consumption causes Nobel Prize winning. This conclusion is
flawed because of: A. Selection bias B. Ecological fallacy C. Confounding by indication
D. Recall bias
B. Ecological fallacy [CORRECT]
,2
Rationale: The ecological fallacy occurs when group-level associations are incorrectly
applied to individuals. Country-level data on chocolate consumption and Nobel
laureates cannot establish individual-level causation because the exposure and
outcome were not measured in the same individuals. Wealth, education
infrastructure, and research funding (confounders) likely explain both variables at the
country level. Correct Answer: B
Q3. A study examines the prevalence of hypertension among adults aged 18-65 in a
single community health fair during one weekend. Which study design is this? A.
Case-control study B. Cohort study C. Cross-sectional study D. Randomized
controlled trial
C. Cross-sectional study [CORRECT]
Rationale: A cross-sectional study measures exposure and outcome simultaneously at
a single point in time (or brief period), providing a "snapshot" of disease prevalence
and exposure distribution. This design cannot establish temporal sequence (which
came first) and is therefore limited for causal inference. It is useful for generating
hypotheses and planning health services. Correct Answer: C
Q4. A researcher identifies 200 women with breast cancer and 400 women without
breast cancer, then retrospectively assesses their lifetime oral contraceptive use.
Which study design is this? A. Prospective cohort study B. Retrospective cohort study
C. Case-control study D. Ecological study
C. Case-control study [CORRECT]
Rationale: A case-control study begins with the outcome (disease status: cases with
breast cancer, controls without) and looks backward in time to compare exposure
history (oral contraceptive use). This design is efficient for rare diseases and requires
fewer subjects than cohort studies, but is susceptible to recall bias and selection bias
in control recruitment. Correct Answer: C
, 3
Q5. Which of the following is the PRIMARY advantage of a randomized controlled
trial (RCT) over an observational cohort study? A. RCTs can study rare diseases more
efficiently B. RCTs eliminate confounding through randomization, creating
comparable groups C. RCTs require smaller sample sizes to achieve the same power
D. RCTs can measure incidence rates more accurately
B. RCTs eliminate confounding through randomization, creating comparable groups
[CORRECT]
Rationale: Randomization distributes both known and unknown confounders evenly
between intervention and control groups, minimizing confounding bias and
strengthening causal inference. This is the fundamental advantage of RCTs. However,
RCTs are often expensive, have limited generalizability, and may be unethical for
harmful exposures. They do not necessarily require smaller samples or study rare
diseases more efficiently. Correct Answer: B
Q6. In a cohort study of 1,000 smokers and 1,000 non-smokers followed for 10 years,
150 smokers and 30 non-smokers developed lung cancer. What is the relative risk
(RR)? A. 2.0 B. 3.0 C. 5.0 D. 7.5
C. 5.0 [CORRECT]
Rationale: RR = Incidence in exposed / Incidence in unexposed = (150/1000) /
(30/1000) = 0..03 = 5.0. This means smokers have 5 times the risk of lung
cancer compared to non-smokers. The RR is appropriate for cohort studies where
incidence can be calculated because subjects are followed over time. Correct Answer:
C
Q7. In the same smoking study (Q6), what is the attributable risk (AR) in the exposed
group? A. 3 per 100 B. 12 per 100 C. 15 per 100 D. 80 per 100
B. 12 per 100 [CORRECT]
