no. 2.] PSYCHOLOGICAL EXAMINING IN THE UNITED STATES ARMY. 

 Section 2. — Differentiation between normal and feeble-minded persons. 



329 



It is a well-known fact that the value of a test may vary greatly in the different ranges of 

 intelligence. Table 8 shows the relative value of the tests in differentiating between privates 

 and institutional feeble-minded subjects. It will be noted that in this table the rank order of 

 the tests differs greatly from that in table 6. Test 7 has changed from poorest to best, the 

 position of test 10 is greatly improved, and that of test 3 injured. The superiority of test 7 

 over all the other tests of the scale is marked, and the inferiority of test 3 even more so. 



Table 8. — Differentiation between privates and institutional feeble-minded subjects. 



In this connection inquiry was made to find whether institutional subjects tend to make 

 their score chiefly in certain tests. If this were the case it might then be possible so to manipu- 

 late the tests that these subjects would get a significantly lower score than the privates. The 

 following figures show each test's percentage contribution to total weighted score in the case 

 of 66 institutional feeble-minded (Vineland and Waverly) and 188 privates selected at random 

 (Camp Dix) : 



It is clear from this comparison that the institutional cases make a larger proportion of 

 their total scores in test 5 than do privates. 



Table 9 shows the percentage contribution of each test to total score in various ranges of 

 intelligence : 



Table 9. — Percentage of contribution of each test to total weighted score. 



Tests 1, 2, 4, 5, and 10 make a relatively larger contribution to total score with low than 

 with high subjects, while the reverse holds for tests 3, 6, 7, 8, and 9. Although the above 

 figures taken alone do not furnish a safe index of the relative value of the tests in the different 



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