Let X represents the number of children under 18 years old in an American family. According to the Statistical Abstract of The United States: 1985, the probability distribution of X is as follow:

x

0

1

2

3

4

5

P(X = x)

0.50

0.21

0.19

0.07

0.02

0.01

(a)What is the most likely number of children in a family?

(b)What is the probability of a family's having more than two children?