Life table function

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Life table function  (LIFE table function)

The course of mortality throughout life may be described by a mortality table 1 or life table 1. This consists of one or more life table functions 2, all of which are mathematically related and may generally be derived when the value of one of them is known. The survivorship function 3 shows the number of survivors 4 of a cohort (116-2) of births to exact age x, on the assumption that the cohort is subjected to the rates of mortality shown. The number of births in the original cohort is known as the radix 5 or root 5 of the life table and the process of diminution is known as attrition 6. From a knowledge of the survivorship function it is possible to compute the probability of survival 7 from exact age x to exact age x+ n.

  • 4. The number of survivors to exact age x is denoted by lx.
  • 7. The probability of survival from age x to age x + n is always written npx and from age x to age x + 1: px.


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Departement of Economic and Social Affairs
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