10 free USMLE Step 1 practice questions in the real exam format, covering the official content areas, with an explanation for every answer.
USMLE Step 1 Practice Test 4Tutor mode
Question 1 of 10
Biostatistics & Epidemiology/Population Health
In a randomized, double-blind, placebo-controlled trial, 2000 patients who recently had a transient ischemic attack are assigned to receive a new oral antiplatelet drug or placebo and are followed for 5 years. The number of patients who have a stroke is shown. Based on these results, about how many patients must be treated with the drug for 5 years to prevent one stroke?