Answer:
0.0337 = 3.37% probability of finding two defects.
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.
What is the probability of finding two defects in a Binomial distribution, with a sample size of 30, and probability of 0.2?
This is [tex]P(X = 2)[/tex], with [tex]n = 30[/tex] and [tex]p = 0.2[/tex]. So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 30) = C_{30,2}.(0.2)^{2}.(0.8)^{28} = 0.0337[/tex]
0.0337 = 3.37% probability of finding two defects.