Decide and Conquer: The Ultimate Guide for Improving Your Decision Making, Second Edition

11. Are You Overconfident?

For each of the following ten items, provide a low and high guess such that you are 90 percent sure the correct answer falls between the two guesses. Your challenge is to be neither too narrow nor too wide.¹

How to Score

The correct answers to this quiz are as follows: (1) 39 years; (2) 4,187 miles; (3) 12 countries as of 2014; (4) 39 books; (5) 2,160 miles; (6) 390,000 pounds; (7) 1756; (8) 645 days; (9) 5,959 miles; (10) 36,198 feet.

If you successfully met the challenge—that is, achieved 90 percent confidence—you should have 10 percent misses. That converts to getting nine of the above estimates correct.

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