176 A BIOMETRIC STUDY OF BASAL METABOLISM IN MAN. 



Turning to the square root of mean-square deviation as given in 

 table 68 for our most critical test of the three methods, we find that for 

 the first series of 64 men and for the supplementary series of women the 

 Du Bois height-weight chart gives closer prediction than body-weight. 

 The differences in terms of percentages of the mean heat-production of 

 the groups dealt with are 8.48 7.65 =0.83 per cent for the men and 

 12.96-12.63=0.33 per cent for the women. 



In the Gephart and Du Bois selection, body-weight and body- 

 surface by the Du Bois height-weight chart are equally good as a basis 

 for prediction, differing by only 6.79 6.79 = 0.00 per cent. The origi- 

 nal women also show practical identity in the results of the two methods 

 of prediction, the difference being only 8.878.89 = 0.02 per cent. 



TABLE 68. Square root of mean-square deviation of total heat-production as predicted 

 by linear equations from the actual heat-production. 



Possibly the results slightly favor the prediction of heat-production 

 from the Du Bois height-weight chart, but the differences are by no 

 means so large as would be implied by the statements of those who have 

 urged that heat-production is proportional to body-surface but not to 

 body-weight. Thus, in the instance among the larger series (IV-VII) 

 most favorable to the body-surface theory, i.e., that in which there is 

 a square root of mean-square deviation of 7.65 per cent in predicting 

 the metabolism of the individuals of an unmeasured series from body 

 surface and of 8.48 per cent in predicting from body-weight, the error 

 of prediction is only 8.48 7.65=0.83 per cent greater when body- 

 weight is used as a base. We shall return to these problems in a 

 subsequent section. 



Summarizing the results of these tests of body-surface as measured 

 by the Du Bois height-weight chart in comparison with body-weight 



