Question

What is the probability that a person who is older than 35 years has a hemoglobin level between 9 and 11?

Answer 1

There are some numbers missing in your table. We think the values are supposed to be the ones shown in the attachment.

The number of people that are older than 35 and have a hemoglobin level between 9 and 11 is 46. The total number of people older than 35 is 162, so the proportion of people older than 35 with the hemoglobin level of interest is ...

... 46/162 ≈ 0.284

The appropriate choice is B. 0.284.

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Here's how you get there with the formula for conditional probability.

P(9-11 | >35) = P(9-11 & >35)/P(>35) . . . . conditional probability formula

P(9-11 | >35) = (46/429) / (162/429) = 46/162