If half the batch of 6,000 vials are contaminated, what is the probability of finding no contaminated vials if only two vials are selected from the total amount produced?

Answer 1

Use the binomial distribution.

If you calculate by hand, here is a formula:

P(x) = (nCx)(p^x)[q^(n-x)]

x = 0
n = 2
p = .5
q = 1 - p = .5

Substitute into the formula and calculate.

I hope this will help.