158 A BIOMETRIC STUDY OF BASAL METABOLISM IN MAN. 



variability of the subgroups defined by a given grade of weight or body- 

 surface is given by 



where a h is the standard deviation of heat-production in individuals 

 at large and a hw and a h the standard deviation of heat-production in 

 groups of individuals of the same weight or surface. The results for 

 the major series are summarized in table 54. 



TABLE 54. Percentage of the total variation in heat-production which remains after individuals 

 are classified according to body-weight and body-surface by two formulas. 



The entries in the body of this table show the relative amount of 

 variation in metabolism which remains after individuals are sorted 

 into groups according to body-weight or body-surface by the two 

 formulas. 74 To facilitate comparison merely, the variabilities (standard 

 deviations) of the subgroups of like weight or surface-area have been 

 expressed as percentages of the standard deviation of heat-production 

 in all individuals irrespective of body-weight or body-surface. A 

 cursory inspection of the body of the table shows that the metabolism 

 measurements for any given grade of body-weight or body-surface 

 in the male series exhibit (roughly speaking) 55 or 60 per cent as much 

 variation as measurements made on individuals irrespective of these 

 characters, while in the female series they show from 65 to 90 per cent 

 of the population variability. 



We now turn to a consideration of the actual magnitudes of the 

 correlations for body-weight and heat-production, r wh , and body- 

 surface area and heat-production, r ah , as given in table 53. 



Since body-surface is the character upon which such great emphasis 

 has been laid as a standard in metabolism studies for the past quarter 



74 These are the theoretical values derived from the formulas just discussed. It is useless to 

 compare them with the values computed directly when the number of individuals is so 

 small as it is here. 



