Life table কী?

A life table follows a cohort of individuals born together through their lives. For each age $x$ it records $l_x$, the survivorship — the fraction of the cohort still alive at age $x$ — and $m_x$, the fecundity — the mean number of daughters born to a female of age $x$. From them: the mortality between ages, $q_x = 1 - l_{x+1}/l_x$; the net reproductive rate $R_0 = \sum_x l_x m_x$, the number of daughters a newborn female will have on average in her lifetime; and the generation time $T = \sum_x x\,l_x m_x / R_0$, the mean age of the mothers of those daughters. A population with $R_0 > 1$ grows, with $R_0 < 1$ declines; over one generation it is multiplied by $R_0$.