Survey of the Colon?' Vision of 1000 Students. 



195 



main distribution is subtracted from the observations, and 

 the remainders on the left compared with the small curve, 

 taking the groups singly, P comes out '08 ; we do not know, 

 however, whether the theory can be applied to such a small 

 ] lumber of cases, and in any case the influence of the some- 

 what dubious 3 in the first group now becomes very great. 



150 



100 



5G 



Fio\ 



BLUE-GREEN TEST 



MEN 



P--31 



Abscissae represent distance from focus in millimetres, 

 ordi nates number of observers. 



Fig. 6 gives the results of the blue-green test for the men. 



© © © 



The curve shows their graduation by #o/(l +.A' 2 /« 2 ) m 5 whore 

 ?/ = 128*0, a — 7*244, ?>? = 4*(')24, and the origin is taken at 

 15*55. P works out at "31, so the fit is a good one. 



2 



