140 THE QUANTITATIVE METHOD IN BIOLOGY 



Since 301 fertile plants were raised from 315 seeds, the 

 numencal values of the four terms under consideration no 

 longer represent the frequencies of the four groups in respect of 

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

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

 numerical values are a=^- p = ^. y = ^^ and 8=^. The 

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

 301 X 1 ; 301 X -I ; 301 X f, and 301 x f . 



In MENDEL'S experiment the figures were ^ : 



(tt) Plants bearing Dd seeds . 

 (P) „ Dd and Rd seeds 



(v) „ Dd and Dr seeds 



(S) „ Dd. Dr, Rd and 



Rr seeds 



Observed 



38 

 60 



65 

 138 



Calculated 



301 x^= 33 

 301 xf= 67 

 30ixf= 67 



301x1=134 



Among the plants raised from wrinUed, yellow seeds we can 

 distinguish : 



(e) plants raised from seeds R^d^ ; coefficient i; i sort of 

 seeds (wrinkled, yellow). 



(f) Plants raised from 2drR^ ; coefiicient 2 ; 2 sorts of seeds 

 (wimkled, yeUow; wrinkled, green). 



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

 tained. The numerical values of the terms are ^=-ts, i=Ts- 

 The relative frequencies are therefore i, 2 ; the expected 

 figures are 96 x ^ and 96 x 4. 



In MENDEL'S experiment the figures were : 



(e) Plants bearing Rd seeds . 



(0 „ Rd and Rr seeds 



Observed 



28 



68 



Calculated 



96x^=32 

 96x1 = 64 



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

 tinguish : 



(v) Plants raised from Dh'^ ; coefficient i ; i sort of seeds 

 (round, green). 



(6) Plants raised from 2DRr^ ; coefficient 2 ; 2 sorts of seeds 

 (roimd, green; wrinkled, green). 



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

 The numerical values of the terms are '7 = t5-. ^ = t^- Th^ 

 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. 



