What do you mean?
It's specified in the scenario. He shows you a goat. It's right there. This isn't a variable. It's a fact.
Your only job is to work out whether, given the scenario described, it makes sense to switch. Given all your possible choices.
That’s why this problem is kind of bad. It does not describe the behavior of the host. It describes the perspective of a contestant halfway through the game.
Dumb example. Host flips a coin 9 times in a row and lands heads each time. If you believe this to have happened by chance then it’s probably rigged because that’s insane and it’ll likely be heads again.
If it’s ALWAYS heads then you haven’t learned anything.