Distributions
Why the Bell Curve Is Everywhere
8 min+70 XPStep 1/10
The bell, explained by adding
Heights, test scores, measurement errors, blood pressure — nature keeps drawing the same bell-shaped curve. Why?
The central limit theorem (CLT) has the answer: when an outcome is the sum of many small, independent effects, the total piles up near the average, and extreme sums get rarer the further out you go.
Height = thousands of genes + nutrition + chance. A test score = hundreds of learned facts + sleep + luck. Add enough small dice together and the sum draws a bell — every time.
analogy
Roll one die and every face is equally likely — flat. Roll ten dice and sum them, and totals near 35 dominate while 10 and 60 almost never appear. Adding randomness creates order.