The probability that a person has a certain disease is 0.03. Medical diagnostic tests are available to
determine whether the person actually has the disease. If the disease is actually present, the probability
that the medical diagnostic test will give a positive result (indicating that the disease is present) is 0.90. If
the disease is not actually present, the probability of a positive test result indicating that the disease is
present) is 0.02. Suppose that the medical diagnostic test has given a positive result (indicating that the
disease is present). What is the probability that the disease is actually present given a positive result has
occurred (indicating that the disease is present)?
a. Produce a probability tree on the above question.
b. Use the tabular approach in Excel to answer the above question.