+-------------+-------------+-------------+
| AE. I. | AF. I. | AG. II. |
+-------------+-------------+-------------+
| BE. I. | BF. II. | BG. III. |
+-------------+-------------+-------------+
| CE. II. | CF. III. | CG. III. |
+-------------+-------------+-------------+

First, suppose Ability and Environment to be entirely independent, A
being as frequently associated with E as it is with F or with G;
similarly as regards B and C, then the nine combinations shown in
Table I. will be equally frequent. These tabular entries fall into
three equal groups. The three that lie in and about the upper
left-hand corner contain the highest constituents--namely, either
_high_ combined with _high_, or one _high_ with one _medium_. They
produce Successes of Grade I. The three in the middle diagonal band
running between the lower left and the upper right corners are either
one _high_ and one _low_, or both are _medium_; they will produce
Successes of Grade II. The three in and about the right-hand corner
are either one _medium_ with one _low_, or both are _low_; they will
produce Successes of Grade III. This is still more clearly seen by
sorting the results into Table II., from which it is clear that a
high grade of Success is statistically associated with a high, but
less, grade of Ability, a medium with a medium, and a low grade of
Success with a low, but less low, grade of Ability.

TABLE II.--ABILITY INDEPENDENT OF ENVIRONMENT.
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