You are a contestant on “Who Wants to be a Millionaire?” and have just answered the $250,000 question correctly. If you decide to go on to the $500,000 question and then to the $1,000,000 question, you still have the option available of using the “phone a friend” lifeline on one of the questions to improve your chances of answering correctly. You now want to use decision analysis (including a decision tree and utility theory) to decide how to proceed.