In a clinical trial, blood pressure was measured in a group of patients before and after treatment, which of the following tests will be suitable as a test of significance:

Ans. A. Paired t-testUnpaired t-test (aka Students test) compares two different subjects. The paired t-test reduces intersubject variability (because it makes comparisons between the same subject), and thus is theoretically more powerful than the unpaired t-test.In our case, we are analyzing the same subject twice (that is before and after).