poem

don’t ask why it just came in my head

Quandary

So you have a fair coin that you found on the ground, or at least that’s what everyone says. But on each of N times that you’ve tossed it around, you see every flip has been heads.

For which value of N should you start to suspect that the coin isn’t actually fair? For which values of N can you firmly declare that the tails side is not even there?