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 " " "



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