Since each person is selected at random, we assume that their blood type is independent of each other. Therefore, we can use the multiplication rule of independent events:
P(all four have O+ blood) = 0.47 x 0.47 x 0.47 x 0.47
P(all four have O+ blood) = 0.047^4
P(all four have O+ blood) = 0.00003468 or about 0.0035%
The probability that an African American person in the US has type O+ blood is 47%.
Four unrelated African Americans]are selected at random. Find the probability that all of the four have type O+ blood.
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