All you need to make them realise how the maths works
is to explain to them that they can still pick the door with the goat shown if they like. When they obviously don't, ask them why not. Explain how their decision has changed it to a different game. Ask them if it would affect their choice of switching if, instead of opening another door with a goat, their door was opened and shown to have a goat.
(, Fri 4 Mar 2011, 11:26, Reply)