Which of the following can help control confounding in an epidemiological study?

Correct Answer: D

Rationale: All methods (D) control confounding: randomization (A) balances variables, blinding (B) reduces bias, matching (C) pairs on confounders (e.g., age). Combined, they’re effective.

Correct Answer: B

Rationale: Sensitivity (B) is true positives / (true positives + false negatives), detecting diseased (e.g., 90% sensitivity = 90% of sick identified). A is specificity, C is PPV, D is an error.

Correct Answer: C

Rationale: Higher specificity (C) boosts PPV by reducing false positives (e.g., stricter test). A helps, B and D don’t directly.

Correct Answer: C

Rationale: Quarantine (C) isolates early cases (secondary). A and D are primary, B is treatment.

Correct Answer: A

Rationale: Confounder (A) affects exposure-outcome links (e.g., age). B is error, C is bias, D is a response.