598 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



63 men in the series of 1917 show a general average of 244 <7, with a 

 standard deviation of 46 o-; the individual averages range from 176 

 to 415 (J. Besides the individual with the average of 415 a, which may 

 not be a typical eye reaction, there were 3 other men in the normal 

 series of 1917 who had reaction times of 340 cr or longer, that is: 342, 

 347, and 346 o-. Not one of the 63 subjects had previously served in 

 this measurement. It was deemed of interest to take account of the 

 shortest reactions which the individual subjects made,^ as these 

 minimum reaction times would appear to be less complicated hy 

 fluctuations in attention than is the general average of a series of 

 reactions. The five shortest reactions made by each of the 63 men were 

 therefore averaged. The general average of the 63 minimum averages 

 shows 193 (T, with a standard deviation of 44 c. 



With but few exceptions, all of the eye reactions for the men of the 

 normal series of 1917 were included in the averages. An inspection of 

 the records of prolonged series of reactions taken with other individuals 

 and also in the present low-diet research reveals the fact that fre- 

 quently the first reaction made by a subject is unusually long and 

 apparently quite out of uniformity with the subsequent reactions. 

 On the other hand, these long initial reactions were not invariably 

 found. While on general grounds it is not permissible to omit certain 

 data on the supposition that it fails to fit in with one's standard of 

 normality, yet it is possible to adopt some arbitrary method of deal- 

 ing with such difficulties. The following rules were employed in aver- 

 aging the eye-reaction data for this research: 



(1) If, in the first set of eye reactions taken with a subject, that is, 

 the first time this measurement was made on him, the first two reac- 

 tions were abnormally long (350 <r or longer), they were hoih omitted 

 from the average and considered as preliminary practice. 



(2) Two plates were taken on the subject at each sitting or experi- 

 mental evening. At each subsequent evening after the first, if the 

 first reaction on either plate was abnormally long, it was also omitted 

 from the average and considered as preliminary practice for the 

 evening. 



(3) Abnormally long reactions which occurred at any other places 

 in the records than those specified were invariably included in the 

 averages. 



The individual eye-reaction time averages with standard deviations 

 and coefficients of variability are given in tables 167 and 168 for Squads 

 A and B, respectively. Squad A shows 231 and Squad B 237 a as aver- 

 ages for the first reactions taken from the two groups of men with this 

 technique. The average standard deviation in each case amounts 

 to 20 per cent of the reaction time, the two standard deviations being 



^Diefendorf and Dodge, Brain, 1908, 31, p. 472, 



