Data for the Problem of Evolution in Man. 



303 



the physician and actuary. If their importance were once recognised 

 by the insurance offices, we believe that the necessary data would be 

 readily forthcoming. As illustrations take the following : — 



(i) A man's father dies at 40, and his brother at 25. What is the 

 probable reduction in his own life % Answer : 12 years. 



(ii) A man has two brothers, who die young at 25 and 29. How 

 much will this shorten his probable duration of life % Answer : 14 years. 



(iii) A man's father died at 40, and his brother, his senior by one 

 year, died at 50, twenty-two years ago. A life estate now accrues to 

 the man, whose whereabouts are unknown. What is the probability 

 that he is still alive, and should he return and claim the estate, how 

 long is he likely to enjoy it. Answer : The man belongs to an array of 

 men of mean age 54*99 years at death, and standard deviation 16*41 

 years. Hence the odds against his living beyond 71 years are 835 to 

 165, and, accordingly, the odds against the possibility of his return are 

 about 21 to 4. Should he be alive and return, he is as likely as not 

 to hold it for 6*8 years, and 8*7 years is his expectancy of life, so that 

 the contingency of his being alive and enjoying the estate is worth only 

 about 1*4 years' income of the estate. 



Clearly such problems can be extended in a great variety of ways, 

 which might be serviceable in actuarial practice. 



I.— Correlation Table for the Inheritance of Longevity from Father to 



Son. 



First Series. 



Age of father at death. 



20 



25 



30 



35 



40 



45 



50 



55 



60 



65 



70 



75 



80 85 90 



1 



95 



100 



105 



Totals. 



25 



1 





1 



3 



1 



1 



9 







4 



3 



5 



4 



3 



1 



1 









37 



30 



1 





3 



1 



4 



1 



6 



2 



6 



3 



10 



5 



2 



1 









45 



35 







1 



2 



4 



6 



4 



5 



10 



6 



6 



5 



7 





1 







57 



40 





1 



5 



2 



3 



5 



6 



6 



11 



7 



17 



11 



2 



1 









77 



45 





1 



2 



2 



3 



3 



5 



6 



11 



11 



8 



6 



4 



1 









63 



50 



1 



2 



2 



1 



3 



7 



13 



10 



4 



8 



14 



11 



7 



1 









84 



55 



1 



2 



3 



5 



5 



8 



10 



7 



6 



12 



9 



8 



5 



2 









83 



60 



1 



1 





2 



2 



6 



9 



6 



7 



17 



13 



10 



2 



2 



1 







79 



65 





1 



2 



5 



5 



4 



11 



10 



5 



18 



18 



14 



10 



4 









107 



70 





2 



3 



1 



4 



10 



9 



12 



23 



9 



20 



12 



10 



3 



1 







119 



75 



3 



1 



2 



4 



3 



9 



6 



10 



8 



20 



23 



13 



10 



6 



2 







120 



80 



1 





3 



1 



3 



2 



6 



3 



6 



9 



10 



6 



8 



1 









59 



85 









1 



2 



1 



3 



2 



6 



6 



10 



8 



8 



2 



1 





1 



51 



90 







1 





2 





2 



2 





2 



2 



3 













14 



95 



















2 





1 





1 











4 



100 









































105 













1 

























1 



Totals 



9 



11 



28 



30 



44 



64 



99 



85 



108 



133 



165 



115 



77 



25 



6 







1 



1000 



