Height and weight are two measurements used to track a child's development. The World

Health Organization measures child development by comparing the weights of children who are the

same height and the same gender. In 2009, weights for all 80 cm girls in the reference group had a

mean of

10.2 kg and standard deviation of

0.8 kg. Weights are normally distributed.

a)

What percent of girls who were 80 cm tall in 2009, weighed between 9 kg and 11 kg?

b)

What percent of girls who were 80 cm tall in 2009, weighed less than 7.9 kg?