Birth Rates. The National Center for Health Statistics publishes information about birth rates (per 1000 population) in the document National Vital Statistics Report. The following table provides a frequency distribution for birth rates during one year for the 50 states and the District of Columbia.

Rate Frequency Rate Frequency 9–under 10 3 14–under 15 7 10–under 11 3 15–under 16 1 11–under 12 7 16–under 17 0 12–under 13 19 17–under 18 0 13–under 14 10 18–under 19 1

a. Obtain a frequency histogram of these birth-rate data.

b. Based on your histogram, do you think that birth rates for the 50 states and the District of Columbia are approximately normally distributed? Explain your answer.