Interesting proposal, but I’m thinking it might not be necessarily so. Life expectancy is an average, and averages do not need to be exactly at 50% of the population. That’s the median, you are thinking of the median. It is quite more complicated than that, as there are hundreds of factors that alter life expectancy, thus there are many life expectancy tables depending on gender, lifestyle, cohort, race, income, etc. It will not amount to 50% of the population, specially for populations with a lot of outliers. People who die soon after birth or live exceptionally long lives will skew the average deviating it from a true central tendency. As people live longer and less people die early, then the median (the age at which at least 50% of a cohort, people born the same year, dies) will shift away from the average and occur later. If a lot of teenage and young people die, but the survivors live long lives, then the median will occur sooner. The technical terms are skewness and kurtosis of a probability distribution.
Life Expectancy is the age at which 50% of the of the population is expected to die before.
Submitted 3 weeks ago by Sackeshi@lemmy.world to showerthoughts@lemmy.world
passepartout@feddit.org 3 weeks ago
From Wikipedia:
What you described would be the median, not average.
Zorque@lemmy.world 3 weeks ago
The median is an average. There’s generally three types of average, Mean (what you’re talking about), Median (the one they’re talking about), and Mode (the one rarely talked about).
passepartout@feddit.org 3 weeks ago
Sorry for being nitpicky and thanks for naming them all. I just assume the term average is equivalent to mean average in peoples heads. For uneven distributions, like wealth or life expectancy are I assume, it just wouldn’t be a good measurement.
Flax_vert@feddit.uk 3 weeks ago
Average life expectancy can be misleading. I did the maths with my grandfather’s siblings and him, they had an average life expectancy of like 50. However two died before their first birthday, one died shortly after, then the next one to die was like 58, and the rest were 80-90.