In Chelmsford County Hospital, the probability that a randomly chosen birth results in a boy is 45%. Over the course of a month, there are 20 births at the hospital.

a. What is the chance that more than 14 of the births are boys? Use the method of the normal approximation to the binomial distribution.

b. What is the chance that more than 14 of the births are boys? Use the binomial distribution formula.