This one’s going to blow your mind: it’s called the Monty Hall problem, named after the host of let’s make a deal, and it’s a statistical freak.
Pretend you’re in Let’s Make a deal, and you get to choose 1 of 3 curtains. One of the curtains has a car, the other 2 are a zonk.
You pick curtain 1. Monty hall opens curtain 2 and it’s a zonk. Monty asks you if you want to keep curtain 1 or switch to curtain 3. Do you stay or switch?
You ALWAYS switch, and here’s where it gets F’ing weird. If you switch, you will win the car 2/3rds of the time, not 50% of the time!
If you stay, you will only be right 1/3rd of the time, not 50/50.
The reason why is when you made your choice, you only had 1/3 chance of picking the car. There was a 2/3 chance the car was in the other curtains.
Even when Monty shows you curtain 2 with a Zonk, the original 1/3 and 2/3 odds still remain. They don’t switch to 50/50.
computer simulators have proven it. Super weird.
Monty Hall problem - Wikipedia
