[Vol. XXIII, 1922. J P. C. Mahalanobis : Analysis of Stature. 87 



from the measurements of those below 25, and considered the 

 correlation for the two different age groups separately. 



{b) Age group below 25, total— 125. 



I find for age 



Mean Age = 20-52 years 



S.D. = ^ = 2-2449 years 



For stature, Mean Stature =1649-35 mm. 



S.D.= era, = 6135 



Also ,"1, = Product moment = J- 20- 16 



We notice that the average stature of the lower age group is 

 only 7 mm. less than the general average. The S.D. is also less 

 than the general average, showing that the lower age group is less 

 variable than the general sample. I shall come back to this point 

 later on. 



We find the coefficient of correlation to be 



r— + -1464 + -058 



The correlation is positive but small. It is just on the verge 

 of being significant. The positive character of the coefficient is of 

 course expected, it merely indicates, or rather actually measures 

 the average rate of growth with age. The material includes only 

 a few cases of 16, the lowest age group, and so it is not possible to 

 say very much about the actual variations in the rate of growth. 

 The smallness of the coefficient (if not due to errors of sampling) 

 seems to suggest that the greater part of the increase in stature is 

 attained before the age of 16 or 17. Thus the Anglo-Indian seems 

 to be, so far as stature is concerned, rather precocious in growth. 

 I shall discuss this point after investigating the correlation between 

 age and the other characters. 



(c) Age group above 25, totals 66. 

 I find 



Mean age 



= 3i-38 



years 



S.D.= «r, 



= 6"5765 



years 



Mean Stature 



= 1688-1818 



mm. 



S.D.= <j x 



= 71-072 



mm. 



Product moment = -55*4884 

 Thus, r= -'ii8y±-o8. 



The coefficient is now negative but is scarcely significant in 

 view of its large probable error. A small negative correlation is to 

 be expected in view of the shrinkage which sets in after 25 or 30. 1 



1 Powys: " Anthropometric Data from Australia," Biometrika Vol. I (1902) 

 p. 49- 



