EXAMPLE 4.1 A child psychologist is interested in the number of times a newborn baby's crying wakes its mother after midnight. For a random sample of 50 mothers, the following information was obtained. Let X = the number of times per week a newborn baby's crying wakes its mother after midnight. For this example, x = 0, 1, 2, 3, 4, 5. P(x) = probability that X takes on a value x. X P(x) 0 P(x = 0) = 2 P(x = 1) = 41 50 2 P(x = 2) = 23 50 3 P(x = 3) = - 4 P(x = 4) = 4 5 P(x = 5) = 50 Table 4.2