The Mathematics
The basic algebra used in life tables is as follows.
- : the probability that someone aged exactly will die before reaching age .
- : the probability that someone aged exactly will survive to age .
- : the number of people who survive to age
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- note that this is based on a radix., or starting point, of lives, typically taken as 100,000
- : the number of people who die aged last birthday
- : the probability that someone aged exactly will survive for more years, i.e. live up to at least age years
- : the probability that someone aged exactly will survive for more years, then die within the following years
- μx : the force of mortality, i.e. the instantaneous mortality rate at age x, i.e. the number of people dying in a short interval starting at age x, divided by lx and also divided by the length of the interval. Unlike, the instantaneous mortality rate, μx, may exceed 1.
Another common variable is
This symbol refers to Central rate of mortality. It is approximately equal to the average force of mortality, averaged over the year of age.
Read more about this topic: Life Table
Famous quotes containing the word mathematics:
“Mathematics alone make us feel the limits of our intelligence. For we can always suppose in the case of an experiment that it is inexplicable because we don’t happen to have all the data. In mathematics we have all the data ... and yet we don’t understand. We always come back to the contemplation of our human wretchedness. What force is in relation to our will, the impenetrable opacity of mathematics is in relation to our intelligence.”
—Simone Weil (1909–1943)