Since we cannot use Goddard's results for our purpose above the sixth grade, it is plain that we would not sufficiently approach a random distribution for any age above 11 years. In Minneapolis, for example, a recent census showed 28% of the public school children 12 years of age are in the seventh grade or above, while 6% of the better eleven-year-olds would be excluded by including only those below the seventh grade. We have therefore omitted from our calculations all of Goddard's results for children above eleven years of age as too unreliable for purposes of percentage estimations. Even his eleven-year-olds may be affected. Although it is not clear in the published reports whether the nearest or last birthday was used, Dr. Goddard has informed me that his table shows the results for ages at the last birthday. A child is regarded as six until he has reached his seventh birthday, as is customary. Throughout this book I have followed this method of using age to mean age at last birthday, or _avowed age_. This is in conformity with the common use of age and with general anthropometric practise. It is less confusing and less subject to mistake or errors of record. On the whole, I believe that in statistical work avowed age is preferable to nearest age. TABLE V. PERCENTAGES OF MENTALLY RETARDED CHILDREN TESTED WITH THE 1908 BINET SCALE. (_From Goddard's Table._) ───────────┬───────────┬─────────────────────────────────────────────── │ │ Years Retarded ───────────┼───────────┼───────────╥───────────┬───────────┬─────────── Life-Age │ No. of │Two or more║ Three or │ Four or │ Five or │ cases │ ║ more │ more │ more ───────────┼───────────┼───────────╫───────────┼───────────┼─────────── 5│ 114│ 5.3║ 1.8│ ...│ ... 6│ 160│ 2.5║ 0.6│ 0.6│ ... 7│ 197│ 5.6║ 1.5│ 0.5│ 0.0 8│ 209│ 2.4║ 1.9│ 1.0│ 0.0 9│ 201│ 1.3║ 0.0│ 0.0│ 0.0 │ │ ╟═══════════╢ │ 10│ 222│ 18.9│ 8.1║ 1.4│ 0.0 11│ 166│ 25.9│ 10.8║ 3.0│ 0.6 │ ————│ │ ║ │ │ 1269│ │ ║ │ ───────────┴───────────┴───────────┴───────────╨───────────┴───────────