Central and Dispersion Indicators of Individual Life Duration: New Methods
The secular transition from high to low mortality, and particularly its course during the last decades, has caused profound changes in the length of life. Both the average lifetime and its individual variability have been affected, and this process is still continuing. In this paper, the duration of human life is observed in the light of both central and dispersion indicators. Some new methods are proposed and applied to past and on-going developments.
As to central indicators, we find the three classical statistical averages—mean, median and mode—sufficient and do not propose any others. However, we do consider that the mode deserves more attention than it has been getting because it has properties which contribute to a more balanced understanding of the length of life.
KeywordsLife Table Normal Curve Late Life Central Indicator Demographic Research
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