Monty Hall - The Game and a Simulation.

Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you: "Do you want to pick door No.2?"
Is it to your advantage to switch your choice?


Play the game and see (afterwards) what a simulation says you should have done...

What do you do?