REGRESSION. 





Still another test of the gametic composition of the parents ia the 

 variability of their offspring. The facta regarding such variability 

 are given in table 16. From this table il appears that the mating thai 



Table 16. — Progeny of the various tapes of mating* arranged in order of oariabUUy or ttandard 

 deviation (8. D.), together with the probable errore I P. E. I of tht meant and d* 



also the coefficients of variation {based on tabh 1 : . 



Typo of mating. 



No. of 

 progeny. 



Mean build of pro- 

 geny and (P. I 



Standard di 

 lion and (P I. 



I 

 variabil 



S X 



M x 



Sx 



Sx 



VSx 



VSx 



s .. 



M. . 



F. . 



M . 



S.. 



M . 



M X F . . 



Sx VF. 



FxF.. 



Fx VF. 



VS X F . . 



VF X VF 



M X VF. 



47 



.327 



loo 



300 



11 



28 



.340 



34 



157 



100 



25 



30 



112 



2S 17 

 34.79 

 34 . 39 

 34.01 

 28.55 

 32.18 

 35.41 

 35.68 

 37.56 

 .3S 19 

 35.04 

 39.20 

 37.64 



24 

 15 

 22 

 16 

 86 

 54 

 16 

 51 

 29 

 36 

 83 



78 



o ;.s 



41 

 06 

 13 

 20 

 21 

 22 

 27 

 44 

 37 

 ::s 



(i is 

 6 31 

 9 11 



0.17 

 it II 

 ii L6 

 ii 11 

 it r,i 

 0.38 

 0.11 

 0.36 

 ii 20 

 27 

 59 

 55 

 41 



- 

 11 

 u 

 12 

 14 

 13 



'..7 

 67 



in 

 .;'. 

 7.'. 

 11 



12 06 



17 64 



16 l" 



24 17 



yields the least variable progeny is that of two slender consorts. The 

 variability in their progeny is measured by 2.41 ± 0.17. The varia- 

 bility of the progeny of the VS X S mating is greater, 4.21 ± 0.61, 



Fig. 8. — Line of regression of progeny on*parents based on the difference betwi 

 filial and parental departures from mediocrity. The ab» isure 1 1 1 . 



departure of each class of mating. The ordinates are proportional t<> the filial r.-k:rr- 



but on account of the small number of the progeny the probable error 

 is large, and it is possible that this difference in variability between 

 S X S and VS X S progeny is not a significant one Next to the least 



