430 PEARL— SEX RATIO IN DOMESTIC FOWL. 



In Table X. are given the true analytical constants of the curve, 

 and, in another column, the analytical constants on the assumption 

 of concentration of the frequencies at the mid-points of the classes. 



TABLE X. 



Analytical Constants for Variation in the Sex Rate in Poultry, 

 Various Breeds. Families of id and Over. 



Frequencies Supposed Concen- Frequencies Supposed Concen- 



trated at Centers of Gravity trated at Mid-points of 



Constant. of Class Areas. Class Areas. 



N 1009 1009 



Alean 48-574 49-549 



M2 1.7887 1.8197 



/U3 — .0093 — .2622 



fi^ 11.0082 10.2718 



/3j .000015 .0114 



/3, 3-4407 3-IOI9 



K, +.8814 +.1696 



K^ -(- .000013 -\- .0506 



Type VII. IV. 



Mode 48-574 50-231 



Skewness — .0015 + .0264 — .0506 + .0027 



.Vo 315-25 42-740 



The equations to these curves are as follows : 

 True curve : 



-9.3072 



^ = 315.25(1+^^) 



Mid-point curve : 



-17.0718 tan-l (x/11.2271) 



y = 42.7407 ~o vn:^ 



V "*" 126.0478 j 



The fitted curves and the histograms are shown in Figs. 2 and 3. 

 From the data and the diagrams, the following points are to be 

 noted: 



1. The distribution of the sex ratio about the mean value is ap- 

 proximately symmetrical, and, if sufificiently large families are used, 

 leads to high contact of the curves at both ends of the range. 



2. The distribution is apparently more skew than it actually is 

 because of the fact that this graphical representation makes no ac- 



