194- Dr. Houstoun and Miss Dimlop on a Statistical 



15'47, <r = 2*839 and its area =821*9,. and a small one with 

 its mean at 3*7, o- = 2*5 and its area =13*8. These values 

 were obtained by trial and error. The curve thus obtained 

 is represented by the full line in fig. 5 and gives P = *71, 

 t. e: in 71 out of 100 trials we should get in random sampling 



Fig-. 5. 



!20 



60 h 



40 



RED-GREEN TE5T 

 MEN 



Abscissae represent distance from focus in millimetres, 

 ordinates number of observers. 



a fit as bad or worse. Since the first ten observations were 

 grouped, this *71 is no guarantee for the presence or shape 

 of the small curve, only for the main distribution being a 

 very 



o-ood fit to the Gaussian formula. If the calculated 



