Explain why each of the following is or is not a valid probability distribution for a discrete random variable x: See p.183-84. 4.16 Toss three fair coins and let x equal the number of heads observed. A. Identify the sample points associated with this experiment and assign a value of x to each sample point. B. Calculate p(x) for each value of x. c. Construct a probability histogram for p(x). D. What is P(x = 2 or x = 3)?