no. 3] PSYCHOLOGICAL EXAMINING IN THE UNITED STATES ARMY. 



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The intelligence of the draft in terms of the theoretical combined scale derived in chapter 2 

 is shown in table 165. These figures transformed into percentiles are given herewith in table 332 

 and graphically in figure 50. The values of the class intervals of the combined scale have been 

 transmuted into terms of mental age in table 333 and figures 51 and 52. This transmutation 

 was made, not by the regression equation, but by equating the means of the experimental group 

 in terms of combined scale and of mental age and multiplying deviations from the mean of the 

 combined scale by the ratio of the two standard deviations. These tables and graphs include 

 also, for purposes of comparison, the negro draft, white officers, and groups of men examined 

 individually. The transmutation into mental age is given because those terms have now 

 acquired some absolute meaning and are therefore familiar. Rejections from the Army as well 

 as special treatment of the feeble-minded in civil fife can be thought of best in relation to units 

 of mental age. On the other hand, as we have just seen, it may be necessary to revise our 

 notion of the frequency of occurrence of these various levels of intelligence. We know now 

 approximately from clinical experience the capacity and mental ability of a man of 13 years 

 mental age. We have never heretofore supposed that the mental ability of this man was the 

 average of the country or anywhere near it. A moron has been defined as anyone with a mental 

 age from 7 to 12 years. If this definition is interpreted as meaning anyone with a mental age 

 less than 13 years, as has recently been done, then almost half of the white draft (47.3 per cent) 

 would have been morons. Thus it appears that feeble-mindedness, as at present defined, is of 

 much greater frequency of occurrence than had been originally supposed. 



Table 332. — Per cent distribution on combined scale of officer and draft groups. 



