Calculate class boundaries and find the scale for the horizontal axis, multiplying by frequency.

Step 1: Calculate class boundaries.
Class boundaries are found by taking the average of the upper limit of one class and the lower limit of the next class. The gap between the upper limit of a class and the lower limit of the next class is $10 - 9 = 1$. Half of this gap is 0.5.
To find the lower class boundary, subtract 0.5 from the lower class limit.
To find the upper class boundary, add 0.5 to the upper class limit.

For each class:

• For $0-9$: Lower boundary $= 0 - 0.5 = -0.5$, Upper boundary $= 9 + 0.5 = 9.5$.
• For $10-