Table:
age group at symptom onset

15 to 19
20 to 29
30 to 39
40 to 49
50 or older

mean age at symptom onset
15.6
24.7
34.2
43.3
56.0

mean age at diagnosis
26.0
28.9
38.7
45.9
58.0

mean years between symptom onset and diagnosis
10.5
4.3
4.5
2.6
2.0

Statement: the gap between symptom onset and diagnosis was longer for people whose symptoms began before age 20 compared with those whose symptoms appeared at ages 30 to 39.
Question: for people whose symptoms began before age 20 and those whose symptoms appeared at ages 30 to 39,which group of people have longer gap between symptom onset and diagnosis?
Answer: 15 to 19