Frequency Of Different Degrees Of Intelligence
Before we can interpret the results of an examination it is necessary to know
how frequently an I Q of the size found occurs among unselected children. Our
tests of 1000 unselected children enable us to answer this question with some
degree of definiteness. A study of these 1000 I Q's shows the following
significant facts:--
The lowest 1 % go to 70 or below, the highest 1 % reach 130 or above
"
" 2 % " " 73 " " " " 2 % " 128 " "
" " 3 % " " 76 " " " " 3 % " 125 " "
" " 5 % " " 78 " " " " 5 % " 122 " "
" " 10 % " " 85 " " " " 10 % " 116 " "
" " 15 % " " 88 " " " " 15 % " 113 " "
" " 20 % " " 91 " " " " 20 % " 110 " "
" " 25 % " " 92 " " " " 25 % " 108 " "
" " 33+1/3% " " 95 " " " " 33+1/3% " 106 " "
Or, to put some of the above facts in another form:--
The child reaching 110 is equaled or excelled by 20 out of 100
" " " (about) 115 " " " " " 10 " " "
" " " " 125 " " " " " 3 " " "
" " " " 130 " " " " " 1 " " "
Conversely, we may say regarding the subnormals that:--
The child testing at (about) 90 is equaled or excelled by 80 out of 100
" " " " " 85 " " " " " 90 " " "
" " " " " 75 " " " " " 97 " " "
" " " " " 70 " " " " " 99 " " "