────────────────────┬────────────────────────────────────────────────── │ RETARDATION ────────────────────┼────────────────────────────────────────────────── │ Percentage Retarded at Each Life-Age ────────────────────┼──────────┬────┬────┬────┬────┬────┬────┬────┬──── │ Index │ 8 │ 9 │ 10 │ 11 │ 12 │ 13 │ 14 │ 15 ────────────────────┼──────────┼────┼────┼────┼────┼────┼────┼────┼──── School Boys │ =39%=│ 8│ 16│ 24│ 31│ 35│ 40│ 45│ 43 Delinquent Boys │ =70%=│ 0│ 44│ 50│ 67│ 58│ 60│ 77│ 93 School Boys │ =36%=│ │ │ │ │ │ │ │ Glen Lake Boys │ =86%=│ │ 17│ 50│ 46│ 66│ 81│ 61│ 87 School Girls │ =35%=│ 7│ 12│ 16│ 25│ 31│ 33│ 37│ 93 Delinquent Girls │ =90%=│ 0│ 100│ 50│ 50│ 75│ 83│ 95│ 100 ────────────────────┼──────────┼────┴────┴────┴────┴────┴────┴────┴──── │ Index │Average Amount of Retardation in Years ────────────────────┼──────────┼────┬────┬────┬────┬────┬────┬────┬──── School Boys │ =.61 Yr.=│ .09│ .19│ .31│ .43│ .54│ .63│ .78│ .64 Delinquent Boys │=1.27 Yr.=│ .00│ .66│ .50│ .86│1.09│1.11│1.23│2.11 School Boys │ =.54 Yr.=│ │ │ │ │ │ │ │ Glen Lake Boys │=1.54 Yr.=│ │ .17│ .50│ .62│1.25│1.86│2.11│2.03 School Girls │ =.64 Yr.=│ .07│ .15│ .22│ .34│ .45│ .50│ .59│ .82 Delinquent Girls │=2.29 Yr.=│ .00│1.00│1.00│1.00│1.25│2.25│2.05│2.84 ────────────────────┼──────────┼────┴────┴────┴────┴────┴────┴────┴──── │ Totals │ Number of Children at Each Life-Age ────────────────────┼──────────┼────┬────┬────┬────┬────┬────┬────┬──── School Boys │ 13,123│1650│1624│1614│1552│1742│1647│1647│1647 Delinquent Boys │ 213│ 3│ 9│ 6│ 21│ 25│ 47│ 56│ 46 Glen Lake Boys │ 108│ 0│ 6│ 8│ 13│ 12│ 21│ 18│ 30 School Girls │ 12,781│1634│1617│1594│1623│1552│1587│1587│1587 Delinquent Girls │ 82│ 2│ 1│ 2│ 2│ 4│ 12│ 21│ 338 ────────────────────┴──────────┴────┴────┴────┴────┴────┴────┴────┴──── Index equals the sum of retardation at each age multiplied by the number of delinquents at that age divided by the total number of delinquents. From the indices of frequency of retardation in Table XIV it will be seen that retardation of one or more years below the standard of age 7 in the first grade is nearly twice as common among the ordinary delinquent boys as among a group of school boys of corresponding ages, while it is fully 2½ times as great among the ordinary girl delinquents as among a corresponding group of school girls, when estimated on the same basis.