Question

75% of people with this condition have underdeveloped collar bones. There's 6 people. What's the probability that exactly 1/6 has an underdeveloped collarbone

Answer 1

0.0044 = 0.44%

Explanation:

First we have a combination problem:

we have 6 people, and want to make groups of 1 person, so first we calculate the binomial, and then multiply by the probabilities of each case:

C(6,1) = 6!/5! = 6

The probability of people having the condition is 0.75 (just one person), so the probability of people not having it is (1 - 0.75) = 0.25 (five people)

So, the final probability will be:

P = C(6,1) * 0.75 * (0.25)^5 = 0.0044 = 0.44%