A distribution of grades for an introductory statistics class (where A = 4, B = 3, etc) are as follows: X 0 1 2 3 4 P(X) .10 .15 .30 .30 .15 A. A graduate student needs at least a B to get credit for the course. What are her chances of getting at least a B? ___________ B. Find P(1 < 3) ___________ C. Find the average grade in the class __________ D. Find the standard deviation of the class grades ___________