Natality. Table 5.4 is a pmf for the age of mothers of newborns in the United States.

(a) If we select a birth at random, what is the probability the mother is 19 years of age or younger?

(b) What is the probability she is 30 years of age or older?

(c) What is the expected age of the mother at birth? (Use age midpoints for your calculations.)

(d) What is the variance of mothers’ ages?