Recall: One property of the bell-curve (normal distribution) is that it has a predictable percent of values within any given region. The picture at the right is a picture of the empirical rule for the normal distribution. Use this picture to answer the following questions below.

Situation: In a certain population of adult sharks, the mean length is 12 feet, and the standard deviation from the mean is 0.5 feet.

a) What percent of these adult sharks are between 11 and 13 feet long?

b) Fill in the blanks:  68% of these adult sharks are between and feet long?