A mathematics test of 100 multiple- choice questions is to be given to all freshmen enetring a large university. Initially, in a pilot study the test was given to a random sample of 20 freshmen. Suppose that, for the population of all entering freshmen, the distribution of the number of correct answers would be normal with a variance of 250. A. what is the probability that sample variance would be less than 100? B. what is the probability that sample variance would be more than 500.