Using the binomial distribution, it is found that there is a 0.011 = 1.1% probability that exactly one of their four children will have that trait.
For each children, there are only two possible outcomes, either they have the trait, or they do not. The probability of a children having the trait is independent of any other children, hence, the binomial distribution is used to solve this question.
Binomial probability distribution
[tex]P(X=x)=C_{n,x.}p^x.(1-p)^{n-x}[/tex]
[tex]C_{n,x}=\frac{n!}{x!(n-x)!}[/tex]
The parameters are:
In this problem:
The probability is P(X = 1), hence:
[tex]P(X=x)=C_{n,x.}p^x.(1-p)^{n-x}[/tex]
[tex]P(X=1)=C_{4,1*}(0.85)^1.(0.15)^3=0.011[/tex]
0.011 = 1.1% probability that exactly one of their four children will have that trait.
A similar problem is given at https://brainly.com/question/24863377