#### Answer

Class interval is the range that describes a certain category of values, for example, ages 16-25 is a class interval. Class frequency is the amount of data within a class interval, for example, there might be 10 people that in the interval of ages 16-25. The class intervals create the x-axis in a histogram and the class frequency creates the y-axis.

#### Work Step by Step

Use the definitions of class interval and frequency to explain what they are and how they are used in making a histogram.