A student compares the proportion of needle-stick injuries among interns versus postgraduates using a 2x2 table. Several expected cell frequencies are less than 5. The most appropriate test is:

• A Chi-square test with Yates correction
• B Student t-test
• C McNemar test
• D Fisher exact test ✓

Explanation

When any expected cell frequency in a contingency table falls below 5, the chi-square approximation becomes unreliable, and the Fisher exact test is applied instead because it computes the exact probability of the observed table. Yates correction is used for a 2x2 table with an expected frequency just below 5 in larger samples but does not rescue very sparse tables. McNemar is for paired categorical data, which this is not.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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