Question

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

Hemoglobin
Level Person's Age
Less than
25 years 25-35 years Above 35 years Total
Less than 9 21 32 76 129
Between 9 and 11 49 52

Above 11 69
40
Total 139 128 162 429



A.
0.257
B.
0.284
C.
0.312
D.
0.356
E.
0.548

Answer 1

C IS CORRECT

Explanation:

Answer 2

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.

_____

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