72 



TECHNICAL BULLETIN 7 



Number of birds .... 

 Mean total days broody 

 Total days broody standard deviation 

 Mean annual rate .... 

 Annual rate standard deviation 

 Coefficient of correlation 



2245 



23.68 

 ±26.98 



56.48 

 ±9.85 



—.2720 ± .0132 



The coefficient of correlation between days broody and annual rate is nega- 

 tive and of sucli magnitude as to be of considerable significance, were it not 

 for the fact that the two races of birds give a false correlation. 



21. Correlation Between Total Daij.s- Broody and Annual Rate for Broodij 

 Birds Alone — Pullet Year. 



The same group of birds considered in section 12 is used in tliis study. 

 The coefficient of correlation is here used to measure tlie degree of as.soi-iation 

 between degree of broodiness and annual intensity. Constants obtained are 

 the following: — 



PERCENT BROODY 



. A/f^A/ i^lN TER R^TE 



J9/d /9/9 /920 /92/ 

 /E^P HATCHED 



/922 /923 



CiiAHT ]. Relation of ])ercentage of birds broody to mean winter rate hy yc.irs. 



