140 THE QUANTITATIVE METHOD IN BIOLOGY 



Since 301 fertile plants were raised from 315 seeds, th( 

 numerical values of the four terms under consideration n< 

 longer represent the frequencies of the four groups in respect oi 

 the total number of seeds (which is 556), but their relative fre- 

 quencies in respect of the number of plants, which is 301. The 

 numerical values are a = TV; /^ = w; y = TV, and S = j-V The 

 relative frequencies are i, 2, 2, 4 ; the expected figures are 

 301 X ^ ; 301 X f ; 301 X f , and 301 x f , 



In MENDEL'S experiment the figures were ^ : 



(a) Plants bearing Dd seeds . 

 \p) y, Dd and Rd seeds 



(y) ,, Dd and Dr seeds 



(S) „ Dd, Dr, Rd and 



Rr seeds 



Observed 



38 

 60 



65 

 138 



Calculated 



301 xi= 33 

 301 X f = 67 

 301 xf= 67 



301x^=134 



Among the plants raised from wrinkled, yellow seeds we can 

 distinguish : 



(e) plants raised from seeds RH'^ ; coefficient i ; i sort of 

 seeds (wrinkled, yellow). 



(C) Plants raised from 2drR'^ ; coefficient 2 ; 2 sorts of seeds 

 (wrinkled, yellow; wrinkled, green). 



From loi wrinkled, yellow seeds 96 fertile plants were ob- 

 tained. The numerical values of the terms are ^ = -Yt, f=TT- 

 The relative frequencies are therefore i, 2 ; the expected 

 figures are 96 x -^ and 96 x f . 



In MENDEL'S experiment the figures were : 



(e) Plants bearing Rd seeds . 



(f) „ Rd and Rr seeds 



Observed 



28 



68 



Calculated 



96x^=32 

 96x1 = 64 



Among the plants raised from round, green seeds we can dis- 

 tinguish : 



[yf) Plants raised from DH^ ; coefficient i ; i sort of seeds 

 (round, green). 



{B) Plants raised from 2DRr^ ; coefficient 2 ; 2 sorts of seeds 

 (round, green; wrinkled, green). 



From 108 round, green seeds 102 fertile plants were obtained. 

 The numerical values of the terms are ^ = tV, <^ = i%-- The 

 relative frequencies are therefore i, 2 ; the expected figures 

 are 102 x ^ and 102 x f . 



^ Compare MENDEL'S calculation in BATESON, loc. cit., p. 334. 



