300 



MR. (.}. UDNY YULE ON THE ASSOCIATION 



SB are no longer, of course, simple survival rates, and may be greater than unity. 

 This is notably the case for instance with such defects as increase rapidly in old age, 

 e.g., blindness or mental derangement. 



55. Let us turn now to the consideration of Dr. WARNER'S materials. In Table I. 

 below I give the associations observed between the six possible pairs of defects in 

 the two successive investigations, together with the probable errors of the associa- 

 tion coefficients. At the bottom of the table are given the percentages of the 

 children, observed with given defects A, B, C, or D, and with any defect or combination 

 of defects.* The associations observed are on the whole very markedly lower in 

 the second investigation, and the percentages of children with given defects are 

 smaller (except for dulness), but owing to the lower association the total percentage 

 of defective children has risen, in the case of the girls, from 14 '3 to 14'8 per cent. 



TABLE I. Comparison of the Association Coefficients in the Investigations of 1888- 91 

 and 1892-94. A. Development Defects. B. Nerve Signs. C. Low Nutrition. 

 D. Mental Dulness. 



The associations are, however, all high (very high compared with most coefficients 

 of organic correlation with which one has to deal), ranging from 784 to '952. 



* /.., the last figure is 100(1 - (a/3 7 S)/N). 



