which of the following best represents the average speed of a fast runner?

However, the TFR is a reasonable summary of current fertility levels. In particular, the TFR does not necessarily predict how many children young women now will eventually have, as their fertility rates in years to come may change from those of older women now. The TFR (or TPFR-total period fertility rate) is a better index of fertility than the crude birth rate (annual number of births per thousand population) because it is independent of the age structure of the population, but it is a poorer estimate of actual completed family size than the total cohort fertility rate, which is obtained by summing the age-specific fertility rates that actually applied to each cohort as they aged through time. The gross reproduction rate (GRR), is the same as the NRR, except that-like the TFR-it ignores life expectancy. This is a significant factor in world population, due to the high level of gender imbalance in the very populous nations of China and India. But the NRR is particularly relevant where the number of male babies born is very high due to gender imbalance and sex selection. The NRR is less widely used than the TFR, and the United Nations stopped reporting NRR data for member nations after 1998. Total fertility rate for selected countries When the NRR is exactly 1, then each generation of women is exactly reproducing itself. Related parameters Net reproduction rate Īn alternative fertility measure is the net reproduction rate (NRR), which measures the number of daughters a woman would have in her lifetime if she were subject to prevailing age-specific fertility and mortality rates in the given year. Subject to prevailing fertility rates at all ages from a single given year and survives throughout all her childbearing years. In other words, this rate is the number of children a woman would have if she was The TFR represents the average number of children a woman would potentially have, were she to fast-forward through all her childbearing years in a single year, under all the age-specific fertility rates for that year.

The TFR is, therefore, a measure of the fertility of an imaginary woman who passes through her reproductive life subject to all the age-specific fertility rates for ages 15–49 that were recorded for a given population in a given year.

Instead, the TFR is based on the age-specific fertility rates of women in their 'child-bearing years', which in conventional international statistical usage is ages 15–44 or 15–49. Nor is it based on counting up the total number of children actually born over their lifetime. The TFR is not based on the fertility of any real group of women since this would involve waiting until they had completed childbearing. Total fertility rate projections by region

Which of the following best represents the average speed of a fast runner?