The article Term Efficacy of Ribavirin Plus Interferon Alfa in the Treatment of Chronic Hepatitis C, [Gastroenterology (1996, Vol. 111, no. 5, pp. 13071312)], considered

The article €œTerm Efficacy of Ribavirin Plus Interferon Alfa in the Treatment of Chronic Hepatitis C,€ [Gastroenterology (1996, Vol. 111, no. 5, pp. 1307€“1312)], considered the effect of two treatments and a control for treatment of hepatitis C. The following table provides the total patients in each group and the number that showed a complete (positive) response after 24 weeks of treatment. Suppose a patient is selected randomly.

Let A denote the event that the patient is treated with ribavirin plus interferon alfa or interferon alfa, and let B denote the event that the response is complete. Determine the following probabilities.

(a) P(A | B)

(b) P(B | A)

(c) P(A ˆ© B)

(d) P(A ˆª B)

Complete Response 16 Total Ribavirin plus interferon alfa Interferon alfa Untreated controls 21 19 20 6.