This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
[{'content': '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: \nSelect and explain. \nA. Paired t-test, B. Mann-Whitney U test, C. Student t-test, D. ANOVA', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 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).', 'role': 'assistant'}]