ANNUAL PERSISTENCY AND EGG PRODUCTION 



199 



Number of birds 



Mean total days broody . 



Broody standard deviation 



Mean annual persistency . 



Persistency standard deviation 



Coefficient of correlation . 



Regression days broody on persistency 



Regression persistency on days broody 



1037 



4-2.69 

 ±27.33 



294.05 

 ±64:82 

 +.0.532 ±.0209 

 +.022 

 +.126 



Intensity of broodiness, as measured by tbe total days spent in broodiness 

 during the pullet year is subject to wide fluctuations. Its standard deviation 

 shows marked variability in the population. In view of this fact, it seems 

 probable that intensity of broodiness depends on a nunil)er of variables. 



The small and statistically insignificant coefficient of correlation indicates 

 practical independence between degree of broodiness and annual persistency. 



12. Correlation Between Annual Persistency Above the Mean and the Pres- 

 ence of Broodiness. 



This section deals with the absolute relation between tlie presence of the 

 inherited characteristic, broodiness, and persistency greater than the mean of 

 the population studied. Herein lies a definite basis for selection which may 

 or may not be useful in lirceding for high persistency. The following results 

 appear: 



Coefficient of correlation 



—.2081 ±.0139 



The above negative correlation coefficient is statistically significant though 

 it does not reveal an intimate correlation. Eliminating the broody character- 

 istic should in some measure increa.se annual persistency. 



(C) The Rklatiox Betweex Persistency axd FEcrxnixv 



Since high annual persistency appears to be a desirable cliaracteristic to 

 develop from several standpoints, it is highly desirable that its relation to 

 both winter and annual egg record be ascertained. Both relations mav be 

 considered first from the quantitative standpoint and then from the qualita- 

 tive standpoint by use of long and short correlation tables, respectively. 



