Attendance has never been a component of the grade for this course. However, over the years I have noticed that 40% of those who attend regularly receive an above average grade (B or better), while only 10% of those who do not attend regularly receive an above average grade. About 70% of the students attend class regularly. One student is randomly selected at the end of the semester. Find the probability that the student did not attend class regularly given that (s)he did not receive an above average grade

Suppose that 3% of all athletes are using the endurance-enhancing hormone epo (you should be able to simply compute the percentage of all athletes that are not using epo). for our purposes, a “positive” test result is one that indicates presence of epo in an athlete’s bloodstream. the probability of a positive result, given the presence of epo is .99. the probability of a negative result, when epo is not present, is .90. what is the probability that a randomly selected athlete tests positive for epo? 0.0297