Based on the survey of 2,605 students (840+1765), there’s a 32% probability that a randomly selected student has cheated on a test. This is because when you take into account this sample, 840 students out of 2,605 surveyed have cheated on a test. You then divide 840 by 2,605 to get 32% likelihood that a randomly selected person will have cheated on a test before.