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Records of the Indian Museum. [Vol. XXIII, 1922. J 



variation of the larger male organ directly with the variation of 

 the smaller female organ. The same remark also applies to the 

 comparison of large and small built races .... We may take 

 as a measure of variation the ratio of Standard Deviation to mean, 

 or what is more convenient, this quantity multiplied by 100. We 

 shall, accordingly, define V } the coefficient of variation, as the 

 percentage variation in the mean, the Standard Deviation being 

 treated as the total vs nation in the mean .... Of course, it does 

 not follow because we have defined in this manner our " coefficient 

 of variation," that this coefficient is really significant in the 

 comparison of various races ; it may be only a convenient mathe- 

 matical expression, but I believe there is evidence to show that it 

 is a more reliable test of fC efficiency" in a race than absolute 

 variation .... By i( race efficiency," I would denote stability, 

 combined with capacity to play a part in the history of civilisa- 

 tion." 



