A researcher evaluates a new rapid diagnostic test for malaria against blood smear microscopy (gold standard) in 200 patients. Both tests are applied to every patient. The new test detects 75 positives, microscopy detects 70 positives, and both agree on 60 positives. Which statistical test is most appropriate to compare the proportion of positives detected by the two tests?
- A Chi-square test
- B Fisher's exact test
- C McNemar's test ✓
- D Paired t-test
Correct answer: C. McNemar's test
Explanation
McNemar's test is used for paired nominal (binary) data where the same subjects are measured twice. Here both tests are applied to the same 200 patients, making the data paired. Chi-square assumes independence and is inappropriate for paired data. Fisher's exact test is for independent small samples. Paired t-test requires continuous data.
Reference: Park's Textbook of Preventive and Social Medicine, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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