Question

mr and mrs doran have a genetic history such that the probabilty that a child being born to them with a certain trait is 31%. if they have four chidren, what is the probabilty that exaclty one of their four children will have the trait round the nearest thousandth

Answer 1

Use the binomial formula: P(X = 1) = C(4,1) (0.31)^1 (0.69)^3.

C(4,1) = 4, so
P = 4 × 0.31 × 0.69^3 = 4 × 0.31 × 0.328509 = 0.40735116 ≈ 0.407.

So the probability is 0.407 (40.7%).