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.

1 answer

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%