life in Mediocristan is quite enjoyable. It reminds me of Lawrence Durrell's Alexandria. The ocean is nearby, and the climate is pleasant. Never too cold, never too hot.

I want to understand one seemingly irrelevant thing about its population: body weight.

I start taking samples of 100 people. I make my selection randomly. Random places, random times, individuals chosen at random.

After 10 samples, I'm satisfied.

The average weight of my 10 samples is 150 lb.

betting the farm and winning every time

A gambling problem: there is no stock market in Mediocristan, so we have to be creative.

I make the following bet with a counterparty (say, the Mediocristan equivalent of Bear Stearns):

  • take 100 people at random and measure their weight
  • if the average weight is greater than 180 lb. (i.e., 20% higher than the 150 lb. average I estimated), I pay $1 million
  • if the average weight is equal or less than 180 lb., the counterparty pays me $10K

Even though my payout is 1% of the amount I'm risking, I win every time.

Why? Because we are in Mediocristan.

what if the heaviest person in the world lives in my city?

He doesn't. He lives in Mexico or Saudi Arabia, but even if he was visiting here and happened to fall in our selection, the average won't move by much.

He weighs approximately 1300 lb.

Note that we're not talking about "one of the heaviest", but "the heaviest" person in the world. That is, the most extreme element in the entire population.

His presence would move the average from 150 lb. (expected) to 161 lb. (actual).

That is well inside the 180 lb. threshold.

I collect my $10K and go about my day.

Life here is quite enjoyable, unlike Extremistan, where high-confidence bets send you bankrupt.