22 A BIOMETRIC STUDY OF BASAL METABOLISM IN MAN. 



where S(x) and 2(z 2 ) denote the sums of the individual measurements 

 and their squares. 



Furthermore we may write 



where ^(xy] denotes the sum of the product of the two measures under 

 consideration, the bars denote their means, and the sigmas their 

 standard deviations. 



This method is particularly suited for physiological work. The 

 worker has merely to sum the products of the two measures under 

 consideration for all the individuals dealt with, divide by the number 

 of individuals, subtract the product of the means of the two variables 

 from this mean product, and divide the remainder by the product of 

 the two sigmas. The standard deviations are easily obtained by sum- 

 ming the squares of the actual measurements, dividing by the number 

 of individuals, subtracting the square of the mean of the character, 

 and determining the square root of the remainder. 



TABLE 3. Calculation of moments of body-weight and daily heat-production. 



This method gives constants with the maximum degree of exact- 

 ness. It has the special advantage for physiological work that, after 

 the fundamental summations have been made for a first series of experi- 

 ments, subsequent determinations may be added and the correlation 

 on the basis of a larger N determined merely by the addition of the 

 summations of first and second powers and products for the new series. 

 Or, if one suspects that a single aberrant individual, or group of indi- 

 viduals, has too much weight in determining a given coefficient, the 



