the answer is Life expectancy<span> is a statistical measure of the average time an organism is expected to live, based on the year of their </span>birth<span>, their current age and other </span>demographic<span> factors including </span>gender<span>. The most commonly used measure of life expectancy is at birth (LEB), which can be defined in two ways. </span>Cohort<span> LEB is the mean length of life of an actual </span>birth<span>cohort (all individuals born a given year) and can be computed only for cohorts born many decades ago, so that all their </span>members<span> have died.
