Sample Questions
In a life table: = expected number alive at exact age ; = expected number of deaths between ages and x+1. Therefore: Equivalently: (number alive times probability of death).
The curtate expectation of life is:
With constant force , .
Let .
This is a geometric series:
Note: The complete expectation is , while the curtate expectation is slightly less because it only counts complete years survived. Under UDD, , consistent with .
and
Calculate .
For Gompertz, the survival probability is:
Taking logarithms of each:
Dividing:
The answer is 1.949.