Answer:
P(X = 4) = 0.1876
Explanation:
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
![P(X = x) = C_(n,x).p^(x).(1-p)^(n-x)](https://img.qammunity.org/2021/formulas/mathematics/college/mj488d1yx012m85w10rpw59rwq0s5qv1dq.png)
In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.
![C_(n,x) = (n!)/(x!(n-x)!)](https://img.qammunity.org/2021/formulas/mathematics/college/qaowm9lzn4vyb0kbgc2ooqh7fbldb6dkwq.png)
And p is the probability of X happening.
In this question:
![n = 15, p = 0.2](https://img.qammunity.org/2021/formulas/mathematics/college/b275l6qlvq7z9v1zipuy4wz1op8zfiblvl.png)
We want P(X = 4). So
![P(X = 4) = C_(15,4).(0.2)^(4).(0.8)^(11) = 0.1876](https://img.qammunity.org/2021/formulas/mathematics/college/8bjd9rrbikivn3ha4ozh93ytfq1mracdak.png)