128 MAINE AGRICULTURAL EXPERIMENT STATION. I9II. 



birds whose egg records during the same period are shown in fig. 

 80, (p. 157). 



Table A. 



Mortality Records of Adult Females During the Period 

 i8p8 to ipo/. 





Total number of birds 



Number which died 





Laying year. 



put in house. 



during year. 



Percentage mortality. 



1899-1900 



81 



8 



9.9 



1900- '01 



100 



14 



14.0 



1901- '02 



55 



3 



5.5 



1902- '03 



160 



13 



8.1 



1903- '04 



300 



44 



14.7 



1904- '05 



550 



33 



6.0 



1905- '06 



700 



64 



9.1 



1906- '07 



700 



44 



6.3 



1907- '08 



850 



69 



8.1 



The percentage mortality data are shown graphically in fig. 76. 

 The straight line is the graph of the equation 3;^ii.i8 — o.42.;ir 

 where y denotes percentage mortality and x number of years 

 since i898-'99. The line is fitted to the observations by the 

 method of least squares. 



1899-00 190O-C! 



(801-02 1002-03 1S03-04 1904-06 i9<S-06 1906-07 1007-08 



Fig. 76. Diagram showing the percentage mortality of adult female 

 birds during the course of the selection experiment. 



