XXXIV] 



Introduction 



First Variate A. 



lix 



Illustration (ii). Find r^, by mean contingency for the table on p. ix : 



The sum of the positive contingencies is 169'846, or we have mean contingency 

 ■>/r = 'l70, whence the diagram leads us to rj, = '480. The marginal frequencies are 

 the same as in Illustratiori (i). Thus we have 



r = |(-517 + -480) = -499. 

 The table gives actually a true Gaussian distribution with correlation •500. 

 It will be seen from Illustrations (i) and (ii), that if the distribution be Gaussian, 

 even if the marginal frequencies are in fairly irregular groupings, r^ will be 

 reasonably close to the true contingency, and corrected as suggested above will 

 give excellent results. 



h2 



