Table 4: "How many years have you suffered from headaches?" - Synthetic statistics by age.
| Age class | Mean | N | SD |
| Up to 20 | 3.58 | 97 | 2.349 |
| 21-40 | 7.44 | 808 | 5.593 |
| 41-60 | 14.7 | 1042 | 11.271 |
| 60 or more | 24.54 | 371 | 18.223 |
| Total | 13.28 | 2318 | 12.579 |
Significant ANOVA test P-value = 0.000.