THE CLASSES OF FREQUENCY POLYGONS. 25 



Example of calculating the theoretical curve corre- 

 sponding with observed data. (Fig. 4.) 



Distribution of frequency of glands in the right fore leg of 2000 female 

 swine (integral variates): 



Number of glands 012345678910 

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



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



2 2000 998 6148 3872 48568 



vj = 998 -*- 2000 = - .499. 

 y 2 = 6148 -f- 2000 = 3.074. 

 r, = 3872 -* 2000 = 1.936. 

 v 4 = 48568 -*- 2000 = 24.284. 

 H l = M= 4 .499 = 3.501. 

 M 2 = 3.074 ( .499)2 _ 0,304999. 



M 3 = - 1-036 - 8(- .499 X 3.074) + 2(- .499)' = 2.417278. 

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

 _ (2.417278)2 _ 5.843232929 



PS /.i oiijnnn.o i- >.->/.' 3.110823. 



(2.824999) 3 22.545241683 



24.826297 24.826297 

 (2.824999)2 ~~ ?.y061935 



F = 6 -f- 3 X 0.259178 - 2 X 3.110823 = -f 0.555888 (Type I). 

 6(3.11082 - 0.25918 - 1) 



.55589 





d = 1.680774 X .3111 = .5230. 

 d . s= .5230 X 19.9857 = 10.4519. 



b = .840387 4/16 X 20.9857 + 0.25918 X (21.9857)2 = 18.0448. 



18.0448 - 10.4519 

 cti = ~ = o.<96o. 



