Chapter 4.2, Problem 30E

The ages of the nearly 4 million women who gave birth in the United States in 2010 are given in Figure 4.66. Find the mean age of these women.

Age (years)	Number of Women (thousands)
$15\le x<20$	$355.6$
$20\le x<25$	$942.3$
$25\le x<30$	$1,139.9$
$30\le x<35$	$953.5$
$35\le x<40$	$458.4$
$40\le x<45$	$105.9$
$45\le x<50$	$8.0$

Figure 4.66 Ages of women giving birth in 2010.

Source: U.S. Bureau of the Census.