290 PROF. K. PEARSON ON THE MATHEMATICAL THEORY OF EVOLUTION. 
(c.) Bi-parental Inheritance of Stature. 
Table XII.—Correlation as Influenced by Assortative Mating. 
J O 
Class. 
Correlation coefficients. 
Modified by mating. 
Direct. 
Daughters and fathers .... 
•3868 
•3603 
,, mothers .... 
•2528 
•2841 
Sons and fathers. 
•3710 
■3959 
,, mothers. 
•2673 
•3018 
Table XIII.— Regression Coefficients as Influenced by Assortative Mating. 
Class. 
Regression coefficients. 
Modified by mating. 
Direct. 
Daughters on fathers .... 
•2895 
■3096 
„ mothers .... 
•2609 
•2932 
Sons on fathers. 
•4176 
•4156 
„ mothers. 
■2997 
•3384 
Thus we see that both in correlation and regression very sensible differences are 
made by the introduction of bi-parental formulae. 
Table XIV.—Variation in Selected Groups. 
Standard deviations. 
Class. 
(i.) 
(ii.) 
(iii.) 
(iv.) 
All offspring. 
Offspring of 
selected mother. 
Offspring of 
selected father. 
Offspring of 
selected mother 
and father. 
Sons. 
2-617 
2-495 
2-403 
2-300 
Daughters .... 
2-347 
2-250 
2-189 
2-108 
