1909-10.] The Significance of the Correlation Coefficient, etc. 495 
Or dividing by 4 n, 
First Brother. 
Second 
Brother, 
(a, a). 
(a, b). 
(b, b). 
(a, a) . 
22 n — 9 
12 n 
2n 
(a, b) . 
12n 
3271-14 
12 n 
(b,b). . 
2 n 
12 n 
22ti- 9 
a correlation as below 
Size of 
Assortive 
Mating 
r f . m . = '25. 
No Assortive 
Family. 
Mating. 
4 
n— 1 
•407 
•333 
8 
n = 2 
•508 
•428 
16 
n = 3 
•515 
•454 
00 
n — oo 
•555 
•500 
That is, if the hybrid be distinct from the dominant, and an assortive 
mating of the parents equivalent to *25 is assumed, the correlation 
coefficients quickly approach the figures given by observation. 
37. Taking the dominant to include the hybrid we require a different 
parental grouping to give the necessary correlation, namely : — 
Husbands. 
Wives. 
(a, a). 
(a, b). 
(b, b). 
(a, a) . 
7 
8 
1 
(a, b) . 
8 
16 
8 
(b,b). . 
1 
8 
7 
This has a correlation of =§(‘5 — J) = '25 when the dominant includes 
the hybrid. Proceeding as before, we obtain the table of fraternal 
correlation : — 
First Brother. 
Second 
Brother. 
(a, a). 
(a, b). 
(b, b). 
(a, a) . 
(4871-19) 
24?^ 
4n 
(a, b) . 
24n 
5 6n - 26 : 
24n 
(b,b). . 
4:71 
24n 
48w - 19 
