life expectancy

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life expectancy

[′līf ik′spek·tən·sē]
(biology)
The expected number of years that an organism will live based on statistical probability.
(engineering)
The predicted useful service life of an item of equipment.

life expectancy

the number of years the average member of a social group can expect to live. This is largely determined by environmental factors, though improvements in these do not lead to an infinitely extendable life expectancy, since the maximum period of existence of a member of the human species remains at about 110 years and biological factors impose limits less than this for most humans. The average life expectancy at birth in the UK in the late 20th-century was for men 71, and for women 76, and this has changed little in the last half century However, there is variation according to social class and region. Currently these demographic differences are widening, with life expectancy in the north of England and Scotland being significantly less than that in the south. See also BLACK REPORT, DEATH RATE AND MORTALITY RATE.