HEREDITY IN MAN 



103 



number of inches by which the fathers or sons in question 

 differ from the average height of all the fathers (67-5 

 inches) or of all the sons (68-5 inches) respectively. The 

 fact that the average height of all the sons is an inch 

 greater than that of all the fathers need not concern us 

 particularly, as it affects the whole series of sons equally, 

 and a discussion of the reason for the difference would 

 be beyond our present scope. 



Let us consider as an example the fathers of 65-5 inches 

 tall (which class includes all between 64-5 and 66-5 inches), 

 or two inches less than the average (-2 in column 2). 

 There were 237 of these fathers, with the same number 

 of sons. 1 The heights of these sons varied from 60 to 

 74 inches, but the average of them all was 67 inches 

 i.e. 1-5 inches below the average for the total series of 

 sons. 



TABLE i . Inheritance of Stature. All figures are in 

 inches. Correlation = -5. 



Running our eye over the Table we see that it is in- 

 variably the case that fathers measuring so many inches 



1 Owing to the method of arranging the data, both in this Table 

 and in Table 2, the number of fathers is always equal to the 

 number of sons. 



