Bayes’ Theorem—100 Mental Models #068 👽

Your average life expectancy is not average.

Aug 19 · 1 min read
Photo by Nischal Masand on Unsplash

Bayes’ Theorem: Prior knowledge of conditions related to an event can be used to give a more accurate estimation of that event.


Ask yourself, what is my life expectancy? Worldwide, the average life expectancy is 71 years. However, you aren’t average, so your life expectancy isn’t exactly 71. For example, if you’re a woman, have already survived 47 years, have no disease, and live in Australia — then your life expectancy is a lot higher than 71 years.

So we can see that the probability of something, such as life expectancy, is conditional on other factors that are directly related to it.


“The wise man is one who, knows, what he does not know.” ― Lao Tzu, Tao Te Ching

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Tom Chanter

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