6.89 The effect of an antidepressant drug varies from
person to person. Suppose that the drug is effective
on 80% of women and 65% of men. It is known that
66% of the people who take the drug are women.
What is the probability that the drug is effective?
6.90 Refer to Exercise 6.89. Suppose that you are told
that the drug is effective. What is the probability
that the drug taker is a man?
6.91 In a four-cylinder engine there are four spark plugs.
If any one of them malfunctions, the car will idle
roughly and power will be lost. Suppose that for a
certain brand of spark plugs the probability that a
spark plug will function properly after 5,000 miles is
.90. Assuming that the spark plugs operate independently,
what is the probability that the car will idle
roughly after 5,000 miles?
