INFLUENCE OF THE MALE ON LITTER SIZES 
307 
Iii Table I the differences between sires of different birth rank 
as far as breeding qualities are concerned, are in no case signifi- 
cant, if the conventional ratio of the constant being at least 
three times its probable error is assumed. In Table II, the dif- 
ference between singles and twins, .0386 ± .0091 is possibly signifi- 
cant, the others are not. Since five out of six such constants are 
not significant, it is doubtful if the sixth one is, even though the 
chances of its being significant are approximately 216 to 1. 
Of Chester White hogs the following statistics were collected. 
TABLE III. 
BREEDING PERFORMANCE OF CHESTER WHITE BOARS OF 
DIFFERENT BIRTH RANK. 
Birth Rank of Sire 
Number Cases 
Birth Rank of Progeny 
5 
2 
8.0000±.4769 
6 _ ___ 
7 
7.2857±.3531 
7 
31 
65 
7.9644±.2061 
8_ __ 
S.3235+1889 
9 _ _ 
112 
8.1447±.1473 
10 __ 
100 
7.8623±.1542 
11 
54 
7.9466+1894 
12 _ ___ __ 
30 
8.1121±.2013 
13 H 
11 
7.6524±.28177 
14__ _ 
2 
9.0000±.4769 
15 
1 
8.0000 
In no case in Table III is the difference between any two 
types of sires statistically significant. 
Table IV shows the results obtained from a few records on 
Collies. The figures are not comparable statistically, but since 
the evidence is the same as in the previous cases, the data, are 
presented. 
TABLE IV. 
EFFECT OF BIRTH RANK OF SIRE IN COLLIES ON NUMBER 
OF PUPS PER LITTER. 
4. 
5. 
6 . 
7. 
8 . 
Birth Rank of Sire 
Number Cases 
Average Number Progeny 
3 
7 
7 
4 
2 
5.3333+1836 
5.5714+2304 
5.7142+1805 
5.7500±.2500 
.5.0000+ 4769 
