Wesley’s mom discovered a broken window in the living room and went to ask Wesley about it. Wesley told her he had been playing Monopoly with his friend Cindy. She asked him what his last roll had been and he said, “A one”. She immediately knew he was lying.
Monopoly has two dice, and the lowest number two dice can roll is 2. The window repair came out of Wesley’s allowance and he stopped throwing his baseball in the house.
Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.
Which is more probable?
1) Linda is a bank teller. 2) Linda is a bank teller and is active in the feminist movement.
Most people guess number two, but the probability of two events occurring together is always less than or equal to the probability of either one occurring alone. This problem is known as the Conjunction Fallacy.