HHOOniXKSS AM) FKcrNDM^ IN I'OWI. 7V) 



decline is observed until tlie group with six liroociy jhtIixIs is rc.iclicd, nt'U-r 

 wliidi tiie mean egg yield fnlls signilicantly. The jji-ohable error inereases so 

 rajudly due to small numiiers when the elass with eight broody jjeriods is 

 reaehed tiiat very little signifieanee can be attaehed to the mean in this and 

 later elasses. On the whole, this table suggests in a general wav iliat increased 

 liroodiness does lower the annur.l record. 



■yO. Correlation Jieficecu Times Jiroodi/ (ind .linntal E(iii Yield for liroodtj 

 Birds Alone — Pullet Year. 



A true measure of the correlation between times broody and animal pro- 

 duction can only lie found within the liroody population as ))reviouslv staled. 

 In the eight-year period IVl'l broody birds are concerned. This groujt has 

 been tabulated and constants calculated. 



Xiunber of birds ....... 1122 



.Mean times broody ...... 2 89 



Times broody standard de\ iation .... ±1.91 



Mean annual production ..... 161-.89 



Aiuiual production standard de\iation . . . ±45.03 

 Coefficient of correlation ..... —.1791 ± .019.5 



Regression broodiness on production . . . — .007() 



Regression ]iroduction on broodiness . . . — 4.2167 



A negative coefficient of correlation of .1791 ± .0195 indicates that the 

 correlation between times broody and annual ])roduetion may not be consid- 

 ered intimate. Such a constant leads to the assumption that broodiness as 

 measured by periods has played some part in limiting annual production for 

 the eight-year period studied. 



31. Correlation Betzceen Total I>ai/s Brood tj and Annual Production — Pullet 

 Year. 



Broodiness may next be measured in total days for the year. Tliis method 

 of measuring has been made use of between total days l)roody, and annual 

 egg production. The birds u.sed in this tabulation are 2245 in number, both 

 broody and non-l)roody. Constants calculated follow: — 



Xinnber of birds ....... 2245 



Mean total days broody ..... 28.68 



Total days broody standard deviation . . . ±26.98 

 Mean anniuil ]>roduction ..... 173.06 



Annual production standard de\iatiou . . ±46.40 



Coefficient of correlation —.2200 ± .0135 



An interesting and important fact is brought out by the aliove constants 

 in that the correlation between total days broody and annual egg record is 

 negative and of almost the same magnitude as that obtained between times 

 broody and annual egg record (section 29). The deduction that broodiness 

 lowers annual record again seems warranted, but the coefficient obtained in 

 this table is false because of the presence of the genetically diflFerent i>roodies 

 and non-b.roodies. 



