试题
| 时间/天 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 |
| 人数 | 3 | 3 | 5 | 7 | 8 | 13 | 8 | 7 | 4 | 2 |
| 分组 | 频数 | 频率 |
| 3.5～5.5 | 6 | 0.1 |
| 5.5～7.5 | 12 | 0.2 |
| 7.5～9.5 | ||
| 9.5～11.5 | ||
| 11.5～13.5 | 6 | 0.1 |
| 合计 | 60 | 1 |
| 分组 | 频数 | 频率 |
| 3.5～5.5 | 6 | 0.1 |
| 5.5～7.5 | 12 | 0.2 |
| 7.5～9.5 | 21 | 0.35 |
| 9.5～11.5 | 15 | 0.25 |
| 11.5～13.5 | 6 | 0.1 |
| 合计 | 60 | 1 |
=560人．