Monty Hall — run it yourself

Doors 1, 2, 3. One car, two goats. You pick a door; the host (who knows) opens a goat door; now you can stay or switch. Don't trust anyone — run the numbers.

Same columns as the Excel version. Copy this into a sheet and average the last two columns — you should get the same 33% / 67%. (Big runs show only the first 1,000 rows here; the copy button includes them all.)