THE CLASSES OF FREQUENCY POLYGONS. 35 



Example of calculating the theoretical curve corre- 

 sponding with observed data. (Fig. 6.) 



Distribution of frequency of glands in the right fore leg of 2COO female 

 swine (integral variates): 



Number of glands 0123456789 10 

 Frequency 15 209 365 482 414 277 134 72 22 8 2 



Assume the axis yy' ( Vm) to pass through ordinate 4, then: 



f f(VVni) f(VV)* f(V Fm)3 f(V Fm) 



2 2000 998 6148 3872 48568 



= _ 998 -v- 2000 = .499. 

 , = 6148 -f- 2000 = 3.074. 

 , = 3872 -* 2000 = 1.936. 

 i = 48568 -*- 2000 = 24.284. 



= 0; A = 4-. 499 =3.501. 

 , = 3.074 ( .499)2 _ 2.824999. 



, = - 1.936 - 8(- .499 X 3.074) + 2(- .499) = 2.417278. 

 i = 24.284 -4(-.499 X - 1.936) + 6('.249001 X 3.074) - 3(- 499)* = 24.826297 

 (2.417278)2 5.843232929 



(2.H24999) 3 22.545241683 

 !?4. 826297 ?4. 826297 



= 0.259178. 



' < x v!.824999j a 7.98061935 



= 3.110823. 



.259 X (6.111)2 _ _ . 



4(12.443 - .778)(6.222 - 6.778) 



.55589 

 7^r,21.P857 



D- 1.680774 X .3111 = .5230. 

 D a= .5230 X 19.9857 = 10.4519. 



J- .840887 1/16 X 20.9857 -f C.25918 X (21/J857) a = 18.0448. 

 I. -I'"* 8 -"" 8 ", 3.7965. 



