638 



MEMOIRS NATIONAL ACADEMY OF SCIENCES. 



[ Vol. XV, 



We shall now apply these results to the problem of analyzing typical scores in each class 

 interval of a distribution of total scores. Since x u x 2 , x 3 , etc., in the above formulae are dis- 

 tances from their respective means, d is the difference between their sum and the sum of their 

 means. 



Table 157. — Showing the scores in each alpha and beta test and in mental age in terms of standard deviations. 



The table reads as follows: 2.0 S. D. above the mean is 11.73 points in alpha test 1, 15.53 in alpha test 2, 14.11 in alpha 



test 3, andso on. 



With regard to alpha total scores the tests, in the order of their lengths of range, are, 

 beginning with the longest, 2, 1, 3, 6, 8, 5, 4, and 7. (See table 157.) As we ascend the scale 

 of total scores, additional components will probably be added to typical combinations in this 

 order. On this assumption we need to know the multipliers of d in the regression equations 



