Allergic reactions to poison ivy can be miserable Plant oils cause the reaction Researchers at Allergy Institute did a study to determine the effects of washing the oil off within 5 minutes of exposure A random sample of 1000 people with known allergies to poison ivy participated in the study Oil from the poison ivy plant was rubbed on a patch of skin For 500 of the subjects it was washed off within 5 minutes For the other 500 subjects the oil was washed off after 5 minutes The results are summarized in the following table Within 5 Minutes After 5 Minutes 409 66 25 500 Let s use the following notation for the various events W washing oil off within 5 minutes A washing oil off after 5 minutes N no reaction M mild reaction S strong reaction Find the following probabilities for a person selected at random from this sample of 1000 subjects Use 3 decimal places a P N P M P S Reaction None Mild Strong Column Total b P NW P SW c P NA P SA d P N and W P M and W e PIN or M 70 330 100 500 Row Total 479 396 125 1000