1909-10.] The Significance of the Correlation Coefficient, etc. 503 
Table of Parents and Offspring. 
Shorthorn Cattle. 
Mating of Parents. 
Totals. 
Colour of Offspring. 
Red. 
Roan. 
White. 
Number of White 
to be expected. 
Red with Red . 
440 
413 
27 
0 
•44 
(1) 
„ Roan . 
1046 
521 
521 
4 
16 
(2) 
White 
135 
7 
128 
0 
P45 
(3) 
Roan with Roan 
514 
152 
278 
84 
app. 142 
(4) 
„ White 
74 
3 
47 
24 
app. 48 
(5) 
White with White 
3 
3 
(6) 
it is almost inconceivable that any zygote could divide so as to result in two 
absolutely equal zygotes, so that the fact that some red calves are found 
does not mean that a zygote mechanism is impossible. But if red some- 
times dominates white, a small percentage of the reds must be (R, W) in 
constitution. When red mates with red we have out of 440 matings 413 
red and 27 roan calves. Making this a basis of calculation and taking the 
red cattle consisting of a (R, R), and h (R, W), when h represents the mixed 
zygotes among the red animals, we have a (R, R) + /t (R, W), all apparently 
red, mating at random. The resulting calves will be — 
a 2 (R, R) + ah(R, R) + ah(R, W) + 7 i 2 (R, R) + ^ (R, W) + ^(W, W), 
or, 
which gives 
and 
from (1) 
(a + |) 3 (R, R) + h (a + (R, W) + ( W, W), 
H ) 2 = 413 • ' 
K a+ t ) =27 • 
h 
a + n = 2032. 
jU 
from (2) 
So that in this mating 
Further 
h l 
4 
h= 1*33. 
or '44 white calves might be expected. 
- = •0627. 
a 
(1) 
( 2 ) 
VOL. XXX. 
33 
