If we add up the ages of all the people who die in a determined year and we divide by the number of deaths we have the average life span of this population
Q media= 70 + 75 +82+ 23+12+ 56+ 72+ 74+..... / total nº
Mathematical calculations of the mean lifetime
If we add up the ages of all the people who die
in a determined year and we divide by the number of deaths we have the average
life span of this population
Q media=
70 + 75 +82+ 23+12+ 56+ 72+ 74+..... / total nº
If the sample is large, the ages of several individuals
coincide, so that, instead of repeating them in the addition, each age is multiplied
by the number of persons who live to the said age.
Qmedia = n1·t1+ n2·t2+
n3·t3 +... / N
Being N = n1+ n2+n3+....
Some more exact mathematical calculations lead us to the following expressions:
The integral represents the sum of the infinite terms
of the sample with each one multipled by their time of existence before transmuting:
We have substituted dN for its value deriving from the expression::
The integral of the expression leads to:
