Page 50 - University English for non-speacalist

Doubling time is an estimate of how many years
it will take for the number of people living in a given
geographic area to double. Knowledge of this makes it
possible to determine what facilities, products, and
services a given society will require in the future and
the number of years that its planners have to design,
finance and provide these requirements. Total fertility
ratio refers to the average number of children that a
woman in the society under study is likely to have
over her lifetime. Knowledge of this ratio is obviously
very useful for educational authorities for example.
They need to know how many primary schools will be
needed in the future and how many years they have to
build them. Both life expectancy and the infant
mortality rates are useful indications of the well-being
of the population generally and of the health of

49