Assume that a class contains 20 students. If the probability of a student obtaining an "A" is 0.7, a "B" is 0.2 and a "C" is 0.1, answer the following:
(a) What is the probability that 2 students will obtain A's, 2 obtain B's, and 16 obtain C's?
(b) What is this probability if we are given that at least two students receive C's?
(c) If A has a grade value of 4, B has a grade value of 3 and C has a grade value of 1, what is the expected grade of the class? Which law of probability will you use to compute this?