Stern also compiled a table from Chotzen's results which shows this decrease in intelligence quotients with life-age separately for each group of those whom Chotzen by his expert diagnosis regarded as imbeciles, morons, doubtful, and not feeble-minded although attending the special schools (_188_, p. 80). This table is reproduced here as Table XX. On the surface it suggests that the quotients of the extreme groups are nearer together at the older ages, instead of being farther apart. The objection to this evidence from the Binet scale is that the norms are not equivalent for different ages on the scale used. Since the objective norms on the Binet scale are more difficult to attain at the older ages this variation would tend to make older children show lower quotients than the same children would show at younger ages, so that such tables are quite uncertain in significance. TABLE XX. AVERAGE INTELLIGENCE QUOTIENTS OF CHILDREN OF DIFFERENT ABILITY. (From Chotzen's Tables X & XI.) ─────────────┬──────────────┬──────────────┬─────────────┬───────────── LIFE-AGE │ NOT │ DOUBTFUL │ MORONS │ IMBECILES │FEEBLE-MINDED │ DEFECT │ │ ─────────────┼──────────────┼──────────────┼─────────────┼───────────── 8 │ 0.92 │ 0.84 │ 0.76 │ 0.71 9 │ 0.85 │ 0.81 │ 0.77 │ 0.67 10 │ (0.80) │ (0.80) │ 0.74 │ 0.62 11 │ (0.73) │ (0.68) │ 0.71 │ (0.64) 12 │ (0.75) │ (0.75) │ (0.73) │ (0.61) 13 │ │ (0.73) │ │ ─────────────┴──────────────┴──────────────┴─────────────┴───────────── The Jaederholm data with his form of the Binet scale, as treated by Pearson, shows a straight regression line for the backward children which falls below the normal development line on the average four months of mental age for each additional year of life from 7-14 (_167_). Accepting Pearson's interpretation that a year of excess or deficiency and a year of growth is a constant unit, we find that the deficient group from special classes was falling continually behind the normals with increase of age a relatively greater distance from any rational reference point. Pearson accounts for this change in the distance between the two groups of normal and backward children, as I understand his paper, by supposing that with increase in age more and more normal children become deficient. It would seem that this data would be more easily explained by supposing that the distributions became skewed toward deficiency for the older ages, rather than that the distributions remained normal and became flatter.