1 8 RESPIRATORY EXCHANGE OF ANIMALS AND MAN 



minations n. The mean deviation of a single determination or the 

 "standard deviation "Ms then 



A* = 

 and the mean error of the series 



n - i 



As an example I have treated in this way some of the results ob- 

 tained by Benedict and Carpenter in their study of the influence of mental 

 work, upon metabolism. 2 They found in twenty-two double experi- 

 ments on twenty-two subjects that during 3-hour periods of mental 



TABLE III. 



Average 



/2d 2 /i832 At 9-3 



/* = A/ = \\ - = + 9-3. Mean error of series p = = 4- 2*0. 



\M-I \ 21 ^n ^22 



A = 102-4 + 2-0. 



1 A much better name which has not yet come into general use is the " dispersion " of 

 the series of determinations. 



2 U.S. Dep. of Agriculture, 1909. Bull. 208. 



