Step 3 Divide the range by 10 and by 20 to see what interval widths are acceptable;

choose a convenient width. Dividing by 10 gives us 4.8, which we round to 5, and dividing by 20 gives us 2.4, which we round to 3. We decide to go with i ¼ 5. (In Table 2.3, for illustrative purposes we present