Table 4.

Mean differences and ratios between total individual costs (in £ at 1998 prices) by age 28 according to group membership at age 10

Group	Mean difference	t test (significance)	Bootstrap mean difference (95% CI)	Bootstrap ratio (95% CI)
Conduct disorder versus no problem	62 597	4.31 (P<0.001)	62 898 (22 692 to 117 896)	9.95 (3.56 to 20.88)
Conduct problem versus no problem	16 903	5.2 (P<0.001)	16 707 (6 594 to 28 149)	3.45 (1.69 to 6.17)
Conduct disorder versus conduct problem	45 695	3.07 (P=0.003)	46 193 (3 830 to 102 510)	3.04 (1.14 to 6.06)

Bootstrap estimation using 2000 repetitions, bias corrected.