If the events are independent, the probability of both/all events occurring is determined by multiplying the probabilities of the individual events.
Received placebo (1-.80) = .20
Showed improvement (1-.62) = .38
Participants in a study of a new medication received either medication A or a placebo. Find P(placebo and improvement). You may find it helpful to make a tree diagram of the problem on a separate piece of paper.
Of all those who participated in the study, 80% received medication A.
Of those who received medication A, 76% reported an improvement.
Of those who received the placebo, 62% reported no improvement.
1 answer