Consider the information given in Figure 5 - 12, Vulnerable knees. What is the probability that an orthopedic case selected at random involves knee problems? Of those cases, estimate the probability that the case requires full knee replacement. Compute the probability that an orthopedic case selected at random involves a knee problem and requires a full knee replacement. Next, look at the probability distribution for ages of patients requiring full knee replacements. Medicare insurance coverage begins when a person reaches age 65. What is the probability that the age of a person receiving a knee replacement is 65 or older?