Question

it was found that 80 percent of americans victims of healthcare fraud are senior citizens. if 9 victims are randomly selected, find the probability that 5 are senior citizens. round your answers to three decimal places.

P(exactly 5)=

Answer 1

Given X~Binomial(n=9, p=0.8)
P(X=x)=xC9*(0.8^x)*(0.2^(9-x))

So P(X=5)=5C9*(0.8^5)*(0.2^(9-5))=0.06606029

Answer 2

p=.80
n=9
x = number of senior citizens in sample that are victims of fraud

use binomial distribution