Ixiv Tables for Statisticians and Biometricians [VIII IX 



For the given values of h and k we have accordingly: 



r=-TOO, r=--95, 

 d/N=Q, d/./V = -031,756. 

 Thus for d/N=; '02778, we have r = - '9563. 



Accordingly from the table in its original form, we conclude that the 

 association between judgments of sex made by two independent and very com- 

 petent observers from mere inspection of the femora is measured by a tetrachoric 

 correlation of + '956. 



If the reader will use the hyperbolic formula (a) of p. xviii, he will find values of 

 d/N and r identical with those just obtained. 



Illustration (vi). The following data are for the maximum lengths of the long 

 bones in the French male: 



Femur: Mean = 452*28 mm. Humerus: Mean= 33010 mm. 



Standard deviation = 23*72 mm. Standard deviation = 15'38 mm. 



Correlation of femur and humerus = '8421. 



(i) Find the percentage of cases in which a humerus of under 300 mm. will 

 be combined in the same individual with a femur of over 480 mm. 



Here h = 27'72/23'72 = 116863 ; k = - 30-10/15-38 = - 1-95709. 

 Since h is positive, k negative and r positive, we must replace our system by 

 h =116863, k = 1-95709, and r=--8421. 



Our tables for r = '80 and '85 show that for the given values of h and 

 k the required frequency would probably be less than 1 in 50,000,000. We may 

 conclude therefore that no such individuals would probably occur in the total 

 French male population. This is a result the order of which would hardly be 

 appreciated without the aid of the present tables. 



(ii) Find the percentage of cases in which a humerus of under 320 mm. will 

 be associated with a femur of over 460 mm. 



Here h = 7'72/23'72 = '32546 ; k=- 10-10/15-38 = - -65670. 

 Accordingly our system is 



h = -32546, k = '65670, r = --8421. 

 The Tables give for r = - -80 



3 d/N = -009,0146 ; ' 1H dJN = '006,2334. 



K OJ rC / J 



Thus for h = -3, k = '65670, d/N= '007,4377. 



Again h k " 'gl d/N= '006,3352 ; ** *l dfN= "004,3066. 



