Question

The probability that a person in the united states has type b​+ blood is 1212​%. threethree unrelated people in the united states are selected at random. complete parts​ (a) through​ (d).

Answer 1

(a)    P (all B+) = (0.12)(0.12)(0.12)=0.001728=0.1728%

(b)   P (no B+) = (0.88)(0.88)(0.88) = 0.681472=68.15%

(c)    P (not one B+) + P (no B+) = 1

P (not one B+) = 1 – P (no B+)

                             = 1 – 0.681472

P (at least 1 B+) = 0.318528=31.85%

(d)   B. The event in part (a) is unusual because its probability is less than or equal to 0.05.