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 will always eliminate a
door that has a goat whether you pick the car or a goat yourself. You,
of course, don’t know what
is behind your door or the one remaining.
All you know is he eliminated one of the goats. He then says to
you,
"Do you want to pick door No. 2?" Is it to your advantage to switch
your choice? Why or why not?