Page:Kohs-Block-Design tests-1920.pdf/18

 It will, no doubt, be acceded without much question that the block-design tests are less affected by school training than the Binet.

At any rate the total correlational evidence seems to indicate that the block-design tests possess a high degree of reliability.

(5) Conformity of Intelligence Quotient Distribution with Normal Probability

A very necessary index in weighing the reliability of any standardized test is to determine the extent to which an actually found distribution conforms to its theoretical distribution.

In the following table are presented the I. Q.-range distributions for the Binet and the block-design tests. The respective percentage values are compared with what one should theoretically expect.

The average deviation from theoretical expectation for the Binet I. Q. ranges is 3.3 per cent, per I. Q. group. The average deviation for the block-design tests is only 1.4 per cent, per I. Q. group.

In conclusion, one may state that the evidence presented seems to indicate not only that the tests measure intelligence,