Prediction by the Numbers -- NOVA PBS

NARRATOR: The future unfolds before our eyes, but is it always beyond our grasp? What was once the province of the gods has now come more clearly into view, through mathematics and data. Out of some early observations about gambling, arose tools that guide our scientific understanding of the world and more, through the power of prediction. BOATSWAIN'S MATE 1 LUKE SCHAFFER (United States Coast Guard): Keep a good look out. NARRATOR: …every day mathematics and data combine to help us envision what might be. LIBERTY VITTERT (University of Glasgow): It's the best crystal ball that humankind can have. NARRATOR: Take a trip on the wings of probability, into the future. MONA CHALABI (The Guardian, United States Edition): We are thinking about luck or misfortune, but they just, basically, are a question of math, right? The Orange County Fair, held in Southern California: in theory, these crowds hold a predictive power that can have startling accuracy, but it doesn't belong to any individual, only the group. And even then, it has to be viewed through the lens of mathematics. The theory is known as the "wisdom of crowds," a phenomenon first documented about a hundred years ago. Statistician Talithia Williams is here to see if the theory checks out and to spend some time with the Fair's most beloved animal, Patches, a 14-year-old ox. TALITHIA WILLIAMS (Harvey Mudd College): It was a fair, kind of like this one, where, in 1906, Sir Francis Galton came across a contest where you had to guess the weight of an ox, like Patches, you see here behind me. NARRATOR: After the ox weight-guessing contest was over, Galton took all the entries home and analyzed them statistically. To his surprise, while none of the individual guesses were correct, the average of all the guesses was off by less than one percent. But is it still true? TALITHIA WILLIAMS: So, here's how I think we can test that today. What if we ask a random sample of people, here at the fair, if they can guess how many jellybeans they think are in the jar, and then we take those numbers and average them and see if that's actually close to the true number of jellybeans?