Business Weekly conducted a survey of graduates from 30 top MBA programs. On the basis of the survey, the mean annual salary for graduates 10 years after graduation is 145000 dollars and the standard deviation is 39000 dollars. Suppose you take a simple random sample of 65 graduates. Assume that the population of all salaries for MBA graduates is normally distributed. A. Find the probability that a single randomly selected policy has a mean value between 139252 and 141171.3 dollars.
B. Find the probability that a random sample of size n = 98 has a mean value between 139252 and 141171.3 dollars.