One college class had a total of 75 students. The average score for the class on the last exam was 84.4 with a standard deviation of 4.5. A random sample of 31 students was selected a. Calculate the standard error of the mean b. What is the probability that the sample mean will be less than 86? c. What is the probability that the sample mean will be more than 65? d. What is the probability that the sample mean will be between 83.5 and 85 5?