Life expectancy is the expected (in the statistical sense) number of years of life remaining at a given age. It is denoted by ex, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience. (In technical literature, this symbol means the average number of complete years of life remaining, excluding fractions of a year. The corresponding statistic including fractions of a year, the normal meaning of life expectancy, has a symbol with a small circle over the e.) In the modern era, life expectancy has increased so dramatically as to call into question the ability to use current data for very long range predictions into the future.
The term that is known as life expectancy is most often used in the context of human populations, but is also used in plant or animal ecology; it is calculated by the analysis of life tables (also known as actuarial tables). The term life expectancy may also be used in the context of manufactured objects although the related term shelf life is used for consumer products and the terms "mean time to breakdown" (MTTB) and "mean time before failures" (MTBF) are used in engineering l.a.
Read more about Life Expectancy: Interpretation of Life Expectancy, Human Life Expectancy Patterns, Evolution and Aging Rate, Calculating Life Expectancies, Life Expectancy Forecasting, Policy Uses of Life Expectancy, Life Expectancy Vs. Life Span
Famous quotes containing the words life and/or expectancy:
“The East is the hearthside of America. Like any home, therefore, it has the defects of its virtues. Because it is a long-lived-in house, it bursts its seams, is inconvenient, needs constant refurbishing. And some of the family resources have been spent. To attain the privacy that grown-up people find so desirable, Easterners live a harder life than people elsewhere. Today it is we and not the frontiersman who must be rugged to survive.”
—Phyllis McGinley (1905–1978)
“If I had my life over again I should form the habit of nightly composing myself to thoughts of death. I would practise, as it were, the remembrance of death. There is no other practice which so intensifies life. Death, when it approaches, ought not to take one by surprise. It should be part of the full expectancy of life. Without an ever- present sense of death life is insipid. You might as well live on the whites of eggs.”
—Muriel Spark (b. 1918)