90%of a countrys population are a right handed . what is the probability that exactly 29 people in a group of 30 are right handad?

Answer 1

Binomial distribution
p(success) = .9
1-p = .1

P(29 out of 30)

= C(30,29) * .9^29 * .1^1

C(30,29) = 30! / [ 1! (29!) ]
= 30
so
30 * .9^29 * .1 = .1413