According to the Graduate Management Admission ­Council, the average starting salary for an MBA graduate in the class of 2011 was $ 85,854. Assume the population standard deviation for starting MBA salaries was $ 11,700. A random sample of 40 MBA graduates from the class of 2011 was selected. ,a. What is the probability that the sample mean is less than $ 88,000? ,b. What is the probability that the sample mean is more than $ 81,000? ,c. What is the probability that the sample mean is between $ 83,000 and $ 85,000? ,d. Suppose the sample mean was $ 87,400. Does this result support the findings of Graduate Management Admission Council?