Definition
The law of large numbers
Also known as: lln
As you repeat a random trial more and more times, the observed average gets closer to the expected value. Flip a fair coin many times and the proportion of heads tends toward 0.5. Importantly, it does not "balance out" short runs: a streak of heads is never corrected by future flips. Only the long-run proportion settles down, while the raw count of heads can keep drifting.