Probabilistic Inference
with Bayes Rule: Example 2
• Dealer has a bag with two envelopes
– One has a red coin (worth $100) and a black coin
(worth nothing)
– Other has two black coins
• You can choose an envelope and take out a
coin – it’s black.
• You have the option to switch to the other
envelope. Should you switch?
Monty Hall
• 3 doors: a, b, c
– behind two: Goat
– behind one: Prize
• You pick one door, but are not shown
the contents
• Host opens one of the other two doors that has a Goat
• You now have the option to switch to the other unopened door
Should you switch?
*(Goat not
necessarily behind
Door b)
a
b
c