For each of the following ten questions, give the range of answers that you are 90 percent confident contains the correct answer. For example, for the first question, you are supposed to fill in the blanks: "I am 90 percent confident that Martin Luther King's age at the time of his death was somewhere between        years and        years." Don't worry about not knowing the exact answer - and no using Google. The goal here is to see whether you can construct confidence intervals that include the correct answer 90 percent of the time. Here are the ten questions:

If all ten of your intervals include the correct answer, you're under-confident. Any of us could have made sure this occurred - just by making our answers arbitrarily wide. I'm 100% sure Mozart was born sometime between 33BC and say, 1980. But almost everyone who answers these questions has the opposite problem of over-confidence - they can't help themselves from reporting ranges that are too small. People think they know more than they actually know. In fact, when Ed Russo and Paul Schoemaker tested more than 1,000 people, they found that most people missed between four and seven of the questions. Less than 1 percent of the people gave ranges that included the right answer nine or ten times. Ninety-nine percent of people were over-confident.

From Super Crunchers: How Anything Can Be Predicted by Ian Ayres Books by Ian Ayres