A psychologist determined that the number of sessions required to obtain the trust of a new
patient is either 2, 3, 4, or 5. Let be a random variable indicating the number of sessions
required to gain the patient’s trust. The following probability function has been proposed.
() =
14 for = 2, 3, 4, or 5
a. Is this probability function valid? Explain.
b. What is the probability that it takes exactly 4 sessions to gain the patient’s trust?
c. What is the probability that it takes at least 4 sessions to gain the patient’s trust?