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 such 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 Days Broody and Annual Rate for Broody 

 Birds Alone — Pullet Year. 



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

 The coefficient of correlation is here used to measure the degree of association 

 between degree of broodiness and annual intensity. Constants obtained are 

 the following: — 



/E^f? h/^TC/^EP 



CiiAitT 1. Relation of ])ercentage of birds broody to mean winter rate i^y yeans. 



