44 PSYCHOLOGICAL METHODS OF TESTING INTELLIGENCE 



is certainly not usable, because he has included in it also the age- 

 levels of 12 years and over, i. e., children for whom no more ade- 

 quate tests were available from higher levels; the data for these 

 subjects must therefore necessarily be thrown out If we bring 

 together only those children whose area of irregularity is of satis- 

 factory scope, children, then, between 4 and 11 years old, we shall 

 have 1277 children, and it is their percentual distribution that I 

 have computed. In it the percentage of children 'at age' is some- 

 what less, that of children 'above age' is approximately the same 

 as Bobertag, while that of children 'below age' shows a plain, 

 though not very large increase. 



When we stop to think that we have to do in these 

 three investigations not only with children of differ- 

 ent nationality, but also with different examiners, 

 each of whom had his own way of setting the tests 

 and of evaluating them, we can not lay great stress 

 upon what discrepancy exists between the three sets 

 of statistics : we may conclude from them that when 

 a sufficiently large number of non-selected children 

 of different ages are tested, their degree of intelli- 

 gence will be distributed in a somewhat symmetrical 

 fashion. Approximately one-half (in America a 

 scant half) stand at the level of their age; about a 

 fifth (to a fourth) are a year retarded and the like 

 number a year advanced; only a small percentage 

 (at the most 11 per cent.) show more than one year 

 of retardation and a still smaller fraction (at the 

 most 5.5 per cent.) is mentally advanced by more 

 than one year. 



One must be careful not to regard the 'at age' 

 child and the 'normal' child as synonymous terms: 

 on the contrary, the statistical results themselves 

 show that the ' at age ' children simply constitute the 

 middle section of normality, while the children that 

 are one year advanced or retarded are still com- 

 pletely within the bounds of normality. 



