300 



Miss M. Beeton and Prof. Karl Pearson. 



-Diagram giving Mean Age of Fathers at Death for Sons dying at a given Age. 

 Second Series, 1000 cases. 





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45 50 55 60 65 70 75 80 35 90 95 100 105 



Mean Age of Fathers at Death. 



approaching much closer than in the case of sons to the value 

 demanded (0*4) by the Law of Ancestral Heredity. The diagram shows 

 (i) how substantial is the correlation; (ii) how much more nearly the 

 regression line JcJc given by observation approaches the theoretical line 

 Im • and (iii) how very nearly the regression curve is truly linear. 

 The reason of this closer approach to the theoretical value of heredity 

 is owing to the diminution in the non-selective death-rate, the environ 



