168 



BIOLOGY OF DEATH 



tioned merely as illustrations. The whole table is to be 

 read in the same manner. 



From such a table as this it is possible to calculate, 

 by well-known mathematical methods, a single numerical 

 cop.staat of somewhat unique properties known as the 



TABLE 17 



Correlation table showing the correlation ietween father and son in respect 



of duration of life 



DURATION OF LIFE OF FATHER 



coefficient of correlation, which measures the degree of 

 association or mutual dependence of the two variables 

 included in such double entry tables. This coeflSicient 

 measures the amount of resemblance or association be- 

 tween characteristics of individuals or things. It is 

 stated in the form of a decimal which may take any value 

 between and 1. As the correlation coefficient rises to 

 1 we approach a condition of absolute dependence of the 

 variables one upon the other. As it falls to zero 

 we approach a condition of absolute independence, where 

 the one variable has no relation to the other in the amount 



