Based on the data in the two-way table, what is the probability that a person weighs 120 pounds, given that he or she consumes 2,000 to 2,500 calories per day?

In the question "Based on the data in the two-way table, what is the probability that a person weighs 120 pounds, given that he or she consumes 2,000 to 2,500 calories per day?" The probability of an event, say A given another event, say B is given by n(A and B) / n(B). Thus the probability that a person weighs 120 pounds, given that he or she consumes 2,000 to 2,500 calories per day is given by number of persons that weigh 120 pounds and consume 2,000 to 2,500 calories per day / number of persons that consume 2,000 to 2,500 calories per day. From the table, the number of persons that weigh 120 pounds and consume 2,000 to 2,500 calories per day is 10 while the number of persons that consume 2,000 to 2,500 calories per day is 110. Therefore, the required probability is 10 / 110 = 1 / 11

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