Question

what is the size of the class intervals in this graph?

Explanation:

Step1: Identify class - interval endpoints

Look at the x - axis values. The intervals are 5 - 10, 10 - 15, 15 - 20, etc.

Step2: Calculate class - interval size

Subtract the lower limit from the upper limit of a class. For example, for the class 5 - 10, $10 - 5=5$.

Answer:

5