Sec. 4.5 



RECTIFICATION OF THE NORMAL CURVE 



107 



TABLE 4.53 

 A Fictitious Non-normal Frequency Distribution 

 Class Interval / r.c.f. A Class Interval / r.c.f. 



568 



ix = 6.6, approximately; and a = 13.73. 



99 



95 

 90 



80 



$ 60 



§ 50 



£ 40 



"30 



20 



(A)» Normal (Table III) 

 ®ACE scores 



I I I I 1 I 



+ 1 +2 



+1 +2 -2 -1 

 X X 



Figures 4.56. Some graphs of r.c.f. distributions on normal-arithmetic paper. 



It should be evident from Figures 4.56 that the following are true: 



(a) The frequency distribution from Table III yields a perfectly 

 straight line when r.c.f. as a percentage is plotted against A on a 

 normal-arithmetic graph paper. 



(b) The frequency distribution of the ACE scores apparently is 

 quite near to normal because the points of their r.c.f. graph on 



