Answer:
P(X = 4) = 0.1876
Step-by-step 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.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
In this question:
[tex]n = 15, p = 0.2[/tex]
We want P(X = 4). So
[tex]P(X = 4) = C_{15,4}.(0.2)^{4}.(0.8)^{11} = 0.1876[/tex]
