196 Dr. Hou 



stoun and 



Miss Dunlop on a Statistical 



Fig. 7 gives the results of the tests with the black disks for 

 the men. The curve shows the graduation hyy /Cl-t-a; 2 /a 2 ) m , 



and the origin is 



where y Q — 193*5, a = 4*162, m — 3*671, 

 taken at 13*022. P works out at *03. 



If, however, the 



formula y e' vt&n x/a /(l + x 2 /a 2 ) m is used, P becomes *08. 



Fiff. 7. 



2001 



BLACK TEST 

 MEN 



P=-08 



too h- 





J±b= =, 



2J3 



Abscissae represent distance from focus in millimetres, 

 ordinates number of observers. 



Figs. 8, 9, and 10 give the results for the black, red-green, 

 and blue-green tests for the women. The smooth curve in 

 the case of fig. Bis given by y /(l J r x 2 /a 2 ) m , where y = 39*27, 

 a = 3*800 m= 3*319, and the origin is at 12*63. The smooth 



