The U.S. Census Bureau publishes information about ages of people in the United States in Current Population

Question:

The U.S. Census Bureau publishes information about ages of people in the United States in Current Population Reports. A sample of five U.S. residents have the following ages, in years.
21 54 9 45 51
a. Determine the range of these ages.
b. Find the sample standard deviation of these ages by using the defining formula, Definition 3.6 on page 105.
c. Find the sample standard deviation of these ages by using the computing formula, Formula 3.1 on page 106.
d. Compare your work in parts (b) and (c).