Now we calculate the frequencies of each class by adding the number of tallies in each. Note that the sum of all class frequences equals the total number of observations in the sample.
| Intervals | Tally | Frequency |
| 65 - 70 | \\ | 2 |
| 70 - 75 | \\\\ \\ | 7 |
| 75 - 80 | \\\\ \\\\ \ | 16 |
| 80 - 85 | \\\\ \\\\ \\\\ \\\\ \\\\ \\\\ \ | 31 |
| 85 - 90 | \\\\ \\\\ \\\\ \\\\ \\\\ | 24 |
| 90 - 95 | \\\\ \\\\ \\\\ \\\ | 18 |
| 95 - 100 | \\\\ \\\\ \\\ | 13 |
| 100 - 105 | \\\\ \\\\ | 10 |
| 105 - 110 | \\\\ | 5 |
| 110 - 115 | \\\\ | 4 |
| Total | | n = 130 |
