One of the more popular activities this time of year is jelly bean guessing. I have never been too good at it, but I am fascinated with what I learned about the process. 

It turns out that if you ask enough people to guess the number of jelly beans (or any non-random fact), you will arrive close to the correct answer through the average of the whole. It’s a phenomenon known as the Wisdom of Crowds.

In this instance, BBC’s Marcus de Sautoy asked 160 people to guess the number of beans in the jar. Answers ranged from 400 to 50,000! Only four people got “anywhere near” the correct answer. 

But when he averaged all of the answers, he got 4515. The actual: 4510, less than 1% variance from the group guess! It turns out that those who estimate ridiculously low are cancelled out by those whose guess is unrealistically high, and in the end the crowd answer wins.

The science behind this has been applied to more serious endeavors than jelly bean guessing, including locating parameters for lost ships (see Bayesian_search_theory). 

Think of this principle the next time you are tempted to come up with an answer on your own. Although statistics don’t apply for “opinion” questions or value choices, the theory is applicable for settings where you need an answer about something factual. Ask enough people, and you could be much more accurate than if you estimated on your own.

beth triplett

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