Free epidemiology MCQ exam model for clinical students

Explanation:

• Average number of secondary cases from one case → Correct because R₀ reflects transmissibility in a susceptible population.

• Severity of disease → Incorrect because severity is measured by CFR.

• Duration of disease → Incorrect because it does not define R₀.

• Case fatality rate → Incorrect because it measures lethality.

• Proportion of immune population → Incorrect because it relates to herd immunity.

Explanation:

• Incidence and duration of disease → Correct because longer duration and higher incidence increase prevalence.

• Incidence only → Incorrect because duration also affects prevalence.

• Duration only → Incorrect because new cases also matter.

• Mortality only → Incorrect because mortality reduces prevalence.

• Case fatality rate → Incorrect because it measures severity.

Explanation:

• Detects most true cases → Correct because high sensitivity minimizes false negatives.

• Excludes non-diseased individuals → Incorrect because this is specificity.

• Has low false positives → Incorrect because sensitivity relates to false negatives.

• Has high specificity → Incorrect because specificity is different.

• Has high predictive value → Incorrect because it depends on prevalence.

Explanation:

• Selection bias → Correct because it arises from non-random selection of participants.

• Recall bias → Incorrect because it involves inaccurate memory.

• Observer bias → Incorrect because it involves investigator assessment.

• Confounding → Incorrect because it is mixing of effects.

• Measurement bias → Incorrect because it involves faulty instruments.

Explanation:

• Cohort study → Correct because incidence can be measured in exposed and unexposed groups.

• Case–control study → Incorrect because odds ratio is calculated.

• Cross-sectional study → Incorrect because it measures prevalence.

• Ecological study → Incorrect because individual risk cannot be calculated.

• Case series → Incorrect because it lacks comparison groups.

Explanation:

• Correctly identify non-diseased individuals → Correct because specificity measures true negatives.

• Correctly identify diseased individuals → Incorrect because this is sensitivity.

• Detect early disease → Incorrect because it is screening timing.

• Predict disease outcome → Incorrect because it is prognostic.

• Reduce false negatives → Incorrect because sensitivity reduces false negatives.

Explanation:

• Case–control study → Correct because it starts with cases and is efficient for rare diseases.

• Cohort study → Incorrect because it requires large populations.

• Cross-sectional study → Incorrect because it measures prevalence only.

• Randomized controlled trial → Incorrect because it is for interventions.

• Ecological study → Incorrect because it uses group-level data.

Explanation:

• Distribution and determinants of health-related events → Correct because epidemiology studies frequency, patterns, and causes of disease in populations.

• Treatment of individual patients → Incorrect because this is clinical medicine.

• Laboratory diagnosis of disease → Incorrect because this is pathology.

• Drug actions in the body → Incorrect because this is pharmacology.

• Genetic inheritance patterns → Incorrect because this is genetics.

Explanation:

• Randomized controlled trial → Correct because randomization minimizes bias and confounding.

• Cross-sectional study → Incorrect because it is descriptive.

• Case–control study → Incorrect because it is observational.

• Cohort study → Incorrect because it lacks randomization.

• Ecological study → Incorrect because it is hypothesis-generating.

Explanation:

• New cases occurring over a period of time → Correct because incidence reflects disease occurrence rate.

• Total number of cases at a given time → Incorrect because this is prevalence.

• Deaths due to a disease → Incorrect because this is mortality.

• Severity of a disease → Incorrect because it is case fatality.

• Risk factor prevalence → Incorrect because it is exposure frequency.