Blood pressure is recorded in 50 hypertensive patients before starting a new exercise programme and again after 12 weeks in the same patients. The investigator wants to know whether the mean blood pressure changed significantly. Which is the most appropriate test?

• A Unpaired t-test
• B One-way ANOVA
• C Chi-square test
• D Paired t-test ✓

Explanation

The same subjects are measured twice, before and after an intervention, producing matched pairs of observations. The paired t-test compares the mean of the within-subject differences against zero and is the standard parametric test for such designs. The unpaired t-test applies to two independent groups, which is the trap here: identical measurements repeated on the same individuals are not independent samples.

Reference: Mahajan's Methods in Biostatistics for Medical Students and Research Workers, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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