106 PSYCHOLOGICAL METHODS OF TESTING INTELLIGENCE 



mals are used in each term, may assume any value 

 whatever. Thus the mental quotient becomes not 

 only a useful methodological device for the testing 

 of abnormal children, but also a device to be recom- 

 mended for use with normal individuals. We have 

 already mentioned (p. 101) a case illustrative of its 

 application. 



The other difficulty of calculation pertains to the 

 way in which scattered distribution of tests passed 

 is handled in figuring mental age. As is well known, 

 five scattered tests must be passed in order to add 

 one year to the mental age, but no attention is then 

 paid to the years in which these additional tests lie. 

 Let us compare the two hypothetical examples which 

 follow : 



CHILD A. 



All tests through the 6th year are passed : hence the basis 



for computation is a mental level of 6 years 



also passed in Age 7 two tests 1 

 also passed in Age 8 three tests I 

 also passed in Age 9 three tests [ 

 also passed in Age 10 two tests J 



total of 10 tests = 2 years 



Resulting mental level 8 years 



CHILD B. 



All tests through the 6th year are passed : hence the basis 



for computation is a mental level of % 6 years 



also passed in Age 7 three tests ] 

 also passed in Age 8 five tests 

 also passed in Age 9 two tests 

 also passed in Age 10 no tests J 



total of 10 tests 2 years 



Resulting mental level 8 years 



There seems no justification for equating these 

 two children, because the first one really stands de- 

 cidedly higher mentally by dint of his conspicuously 



