Yerkes, InJiibition and Rcmforcement. 



133 



TABLE IV. 



Reaction-time to Electric Stimulation Alone, and to the Same when 



Preceded by a Visual Stimulus. 



' Values were determined by use of the following formulae : 



Mean := 



^ (V. f) 



Probable Error of Mean = ± .6745 



Standard Deviation ^= 



V 



/ 2 (X?. f 



Probable Error of S. D. = ± .6745 

 ^ Probable Error. 



Coefficient of Variation = 

 6 



6 



Mean 



1/ 



S. D. 



2n 



