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Self-test of Overconfidence WB01372_.gif (406 bytes)WB01371_.gif (289 bytes)

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.

Your challenge is to be neither too narrow (ie, overconfident) not too wide (ie, underconfident).

If you successfully meet this challenge, your result should at be least 8 correct (94% likelihood).

You can be 99.9% sure of getting at least 6 correct ...

Source: Confident Decision Making, J. E. Russo & P. J. H. Schowmaker, 1989, Piatkus, London p 71


Question Low High Units
1. Martin Luther King's age at death
2. Length of the Nile River KM MILES
3. Number of countries that are members of OPEC
4. Number of books in the OldTestament
5. Diameter of the moon KM MILES
6. Weight of an empty Boeing 747 KG POUNDS
7. Year in which Wolfgang Amadeus Mozart was born
8. Gestation period (in days) of an Asian elephant
9. Air distance from London to Tokyo. KM MILES
10. Deepest (known) point in the oceans. METRES FEET