SEXUAL ACTIVITY OF MALE RABBITS 597 
TABLE 4 
Service-group coefficients of variability at three different periods 
, i 
SERVICE 
Ist 5th 10th 15th 20th 
AGE — -_— Lond _ s 
iS) 3 iS) iS) re) 
a] nl a] il ‘ 
Oo” on on o@ on 
26 Per cent 26 Percent | s Per cent 26 Percent |28 Per cent 
§ ~~ Sip g » S| » &S 
S5 B35 l= a Beet 
|4 a a Z Z 
days 
Birth | 26)17.62+1.65 
30 23)19.70+1.96 
bo 
(=) 
28.10+3.10) 20,23.03+2.46) 13/15.59+3.39| 16:21.94+2.62 
42.65+4.80) 21/35.53+3.69) 13/52.13+6.91| 11/46.37+6.66 
_ 
(e/2) 
90 23/24.25+2.41| 17/23.89+2.76| 21/19.63+2.04| 11)24.97+3.53] 9/30.91+4.92 
Weighted 
average.. |24.40 31.56 26.11 34.73 31.65. 
3. Service group coefficients of variability 
_ In table 4 are presented the service-group coefficients of vari- 
ability for all of the progeny studied in the experiment. These 
coefficients are obtained in the following manner: The sum of 
the mean individual weights of each litter in the Ist-service 
group was divided by the number of litters, to get an average 
at birth, at thirty days, and at ninety days. The standard 
deviation of this average was then calculated and the coefficient 
of variability (e) obtained by the formula: 
Standard deviation of the average _ 
Average zt 
C 
The same method was used for all five service groups. 
The service-group coefficient of variability differs from the 
litter coefficient of variability given in table 3 in that the former 
measures the range in weight between the individual litter means 
of the different service groups, while the latter is a measure of 
the range in weight between individuals of the same litter. 
The service-group coefficient of variability is valuable in study- 
ing the effects of heavy service of males upon the growth in body 
