You are on a game show with three doors. A car is behind one; goats are behind the others. You pick door No. 9. Suddenly, a worried look flashes across the host's usually smiling face. He forgot which door hides the car! So he says a little prayer and opens No. 3. Much to his relief, a goat is revealed. He asks, "Do you want door No. 2?" is it to your advantage to switch?
W.R. Neuman, Ann Arbor, Mich.
Nope. If the host is clueless, it makes no difference whether you stay or switch. If he knows, switch.
Is Marilyn correct? If not why not?