Question

 A survey found that one out of four Filipinos says he or she has visited a dentist in any given month. If 12 people are selected at random, find the probability that (a) exactly five have visited the dentist last month.

Answer 1

This is a binomial probability with p=0.26, n=12.

$P(X=5)=C_{12}^5).25^5(1-0.25)^{12-5}=0.1032.$