The Galton Board Stock Market Edition is a 12" x 8.5" probability demonstrator providing a visualization of math in motion. This Stock Market Edition simulates the probabilities of a range of monthly market returns from a hypothetical portfolio of stocks and bonds. The Galton Board displays centuries-old mathematical concepts in an innovative, dynamic and demonstration size device. It incorporates Sir Francis Galton’s (1822-1911) invention from 1873 that illustrated the binomial distribution, which for a large number of rows of hexagons and a large number of beads approximates the normal distribution, a concept known as the Central Limit Theorem. According to the Central Limit Theorem, more specifically, the de Moivre (1667-1754) – Laplace (1749-1827) theorem, the normal distribution may be used as an approximation to the binomial distribution under certain conditions. The binomial distribution is altered by the number of rows of hexagons, causing changes to the standard deviation of the resulting bell-shaped curve of beads that land in the bins.
When rotated on its axis, the 6,000 steel beads cascade through rows of symmetrically placed hexagons in the Galton Board. When the device is level, each bead bounces off the hexagons with equal probability of moving to the left or right. As the beads settle into the bins at the bottom of the board, they accumulate to approximate a bell-shaped histogram. Printed on the lower part of the board is the normal distribution or bell curve, along with the average and standard deviation lines relative to that distribution. The bell curve, also known as the Gaussian distribution (Carl Friedrich Gauss, 1777-1855), is important in statistics and probability theory.