64 



TECHNICAL BULLETIN 7 



Coefficient of correlation +.2996 ±; .0386 



Tlie above constant suggests tbat in the 1916 flock there was a rather dir- 

 tinct tendency for broody birds to lay at a higher rate during December than 

 non-broody birds. The constant given in section 3 for the entire period 

 reported upon is -j- .11-66 ±: .01.50. A comparison of the two constants assigns 

 them a similar value in comparison with their probable error, as each is about 

 eight times its probable error. There is the possibility that December rate 

 is higher in the early flock because they were slow to reach sexual maturity, so 

 that winter pause was less pronounced in December than in later flocks. 



5. Correlation Bettaeen the Presence of Broodiness and December Rate above 

 the Mean of Broodies and Non-Broodies Combined — Pullet Year (Improved 

 Flock 1923). 



A total of 404 birds is studied in the 1923 flock, distributed as below: — 



Coefficient of correlation 4-.0695 



.0334 



The degree of correlation amounts to insignificance compared with its prob- 

 able error. It indicates no dependence between the presence of broodiness 

 and December rate above the mean. It is conceivable that early maturity 

 may affect December rate, and winter pause is more pronounced in tlie flocks 

 since the age at maturity lias been reduced. 



6. Correlation Between Times Broody and Winter Rate — Pullet Year. 



This study included 2221 pullets hatched the same seven years as those 

 studied for December rate. Winter rate is calculated on the period from 

 first egg to March first, as already explained. Unpublished data at this Sta- 

 tion indicate a rather intimate correlation between winter rate and annual 

 production. Winter rate was calculated on a greater number of pullets than 

 were studied for December rate, because the latter could only be calculated 

 on individuals hiying one or more eggs in December. The same classes were 

 used in tabulating times broody and winter rate as were used in studying 

 December rate. Constants calculated Are as follows: — 



J 



