Letter of the correct answer and solution

1. Which of the following is a random variable? A. The number of people entering a mall every hour. B. The number of heads appearing in 3 tosses of a single coin. C. The temperature in a certain area recorded every hour. D. All of the above choices are examples of random variable. 2. Which of the following is a mass point of the discrete random variable "number of heads" if a coin is tossed twice? A.(HH) C.0 B. (HHH) D.0.50 3. A certain event has a probability of success as 0.75, what is the probability of failure? A.0.3 B.0.25 C.0.20 D.0. 15 4. For which of the following set of values will make the function f(x) = - a probability mass function (pmf)? A.x = (1,4,9, 16) B.x = [1,2,9,16) C.x = (1,2,3,4 } D.x = 2 3 30 30 ' 30 ' 30)