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

102 Educability and Group Differences
the same California school district on a comprehensive battery of
tests of mental abilities and of scholastic achievement, in addition
to personality inventories and indices of socioeconomic and
cultural disadvantage. It was found that when certain ability and
background factors over which the schools have little or no influence
are statistically controlled, there are no appreciable differences
between the scholastic achievements (as measured by the Stanford
Achievement Tests) of minority and majority pupils. And there is
no evidence of a PAG between all majority and all minority pupils
(who average about 1 a lower) when the differences are measured
in sigma units (Jensen, 1971a).
NOTE
1. Actually, only one element is needed for a simplex, the random G
element in the following model (as would be the case if C = 1 or
was the same constant value for every member of the population).
But this one-element model, consisting of cumulating random
increments, as we shall see, would be too simple to reproduce all
the essential characteristics of the growth curves and intercorrelations
actually found in such characteristics as intelligence, stature, and
achievement, e.g., the predictability or predetermination of the
individual growth curves’ asymptotic values implied by the substantial
heritability of these characteristics.