Consider a shopper will choose either brand A or brand B. On each purchase, the probability that he will choose the same brand that he chose on his last preceding purchase is 1/3, and the probability that he will switch brands is 2/3. Suppose that on his first purchase the probability that he will choose brand A is 1/4 and the probability that he will choose brand B is 3/4. What is the probability that his second purchase will be brand B?

The probability of a thunderstorm on Memorial Day is 0.13 and the probability of a thunderstorm on Independence Day is 0.59. Assuming that these two are Independent, what is the probability of thunderstorms on both Memorial and Independence Day?

If the probability of one event occurring is 1/4 and the probability of another event occurring is 1/10, what is the probability that both events will occur?

A doctor is seeking an anti-depressant for a newly diagnosed patient. Suppose that, of the available anti-depressant drugs, the probability that any particular drug will be effective for a particular patient is p = 0.32. What is the probability that the patient will need toa. take 4 different drugs until the effective one is found. b. take 5 different drugs until the effective one is found. c. take 7 different drugs until the effective one is found.