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The Ohio Journal of Science [Vol. XVIII, No. 4, 



TABLE I. 



Showing the means, M., standard deviations, S. D., and coefficients of variability, 

 Cv., of the respiration composites of the four cows under the experimental con- 

 ditions, before, during, and after feeding. 



Individual Variation. — For clearness and convenience, two 

 sets of comparisons will be made; first, variations within the 

 individual, and second, variations within the group. As 

 stated above, each subject was experimented upon under three 

 different conditions, before, during and after feeding. In order 

 to facilitate comparisons, all three polygons have been plotted 

 upon one sheet, i. e., those which pertain to the individual 

 animal; and at the same time the coefficients of these curves, 

 the mean, standard deviation and coefficient of variability 

 with their probable errors are shown in Table I. 



The general appearance of the composites of all the individ- 

 uals would lead one to believe that the coefficient of variability 

 is the key to their interpretation. The coefficients do bear 

 a relation to the shape of the curve, but in their interpretation 

 they cannot be considered alone, but must be interpreted in 

 terms of the mean and standard of deviation, otherwise they are 

 misleading. For example, the after feeding polygons of Seven 

 H and Three H, (Fig. 3) are entirely different, and a single 

 glance would tell that the polygon of Three H is more variable 

 than that of Seven H, and yet their coefficients of variabihty 

 are practically the same, 42.19 and 41.20 respectively. But 

 considering the means and standard deviations, this is easily 



