Average age of motherとは 意味・読み方・使い方

The net reproduction rate (711-3) and the intrinsic rate of natural increase (703-1) are closely related to one another. The net reproduction rate measures the increase in the stable population (703-2) implied by the given age-specific fertility and mortality rates over a period equivalent to the mean length of a generation ¹ or the mean interval between successive generations ¹. This length of a female generation is equal to the mean age of mothers ² giving birth to live daughters, with current age-specific fertility and mortality rates. Period reproduction rates are current indices (cf. 152) which relate to hypothetical cohorts ³ or synthetic cohorts ³.

• 2. The mean age of fertility, i.e., the mean age of the fertility schedule is only approximately equal to the mean length of a generation. The mean length of a male generation similarly is equal to the mean age of fathers at the birth of their children.

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