Amanufacturer knows that their items have a normal distribution lifespan with a mean of 11. nine years in a standard deviation of 3.9 years. if 4 items are picked at random, 1% of the time their mean life will be less than how many years?

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