Educability-and-Group-Differences-1973-by-Arthur-Robert-Jensen

62 Educability and Group Differences
Mental Group
Percentile
Score
Equivalent
Correct Answers*
I 93-100 89-100
II 65-92 74-88
III 31-64 53-73
IV 10-30 25-52
V 9 and below 1-24
* The number of equivalent correct answers is computed by subtracting from
the number of questions answered correctly one-third of the questions answered
incorrectly
A percentile score of 10 was fixed by Congress as a minimum
passing score, intended to eliminate the 10 percent of the total
draft-age population within the lowest aptitude range of the
distribution of mental test scores (designated as mental group V).
Those in mental group V are disqualified from entering the armed
forces. According to a report from the Office of the Surgeon
General:
The Army has found . . . that an appreciable number of those in
mental group IV (10th to 30th percentile), though they had met
the required minimum requirement on the AFQT, did not
possess sufficient aptitude to assimilate training in even the most
basic military skills. Many of them had to be discharged later
from the Army as inapt or unsuitable. (Karpinos, 1962, p. 11)
The last year for which complete statistics on the AFQT have
been published is 1968 (Office of the Surgeon General, 1969).
They are based on the AFQT scores of 1,009,381 whites and
155,531 Negroes from every state of the continental United States
who were eligible for the draft. (These statistics do not include
Alaska, Hawaii, Guam, and Puerto Rico.)
The percent of each population group with AFQT scores below
the tenth percentile in 1968 were 5-2 percent of whites and 26-8
percent of Negroes. This corresponds to a difference of 1*01 sigma
(a) or standard deviation units. If we put AFQT scores on a scale
with the same standard deviation as the IQ scale in the white
population (er = 15), the difference of l-Olcr would equal 15-15
points. The distributions of whites and Negroes in mental groups
I to IV was as follows: