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
-
- 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:
“It is a monstrous thing to force a child to learn Latin or Greek or mathematics on the ground that they are an indispensable gymnastic for the mental powers. It would be monstrous even if it were true.”
—George Bernard Shaw (1856–1950)
“Why does man freeze to death trying to reach the North Pole? Why does man drive himself to suffer the steam and heat of the Amazon? Why does he stagger his mind with the mathematics of the sky? Once the question mark has arisen in the human brain the answer must be found, if it takes a hundred years. A thousand years.”
—Walter Reisch (1903–1963)