Question: Calculate the width of the class with boundaries 15 and 28.
1. The problem asks to find the width of a class interval given its boundaries.
2. The width of a class interval is calculated by subtracting the lower boundary from the upper boundary.
3. The formula is: $$\text{Width} = \text{Upper boundary} - \text{Lower boundary}$$
4. Substitute the given boundaries: $$\text{Width} = 28 - 15$$
5. Calculate the difference: $$\text{Width} = 13$$
6. Therefore, the width of the class is 13.