Normal distribution sliced to show "68-95-99.7 Rule"

thingiverse

The Normal Distribution, a key topic in probability and statistics, explains that many natural phenomena follow its pattern. A notable property is the "68-95-99.7 Rule," stating that roughly 68%, 95%, and 99.7% of outcomes fall within one, two, or three standard deviations of the mean, respectively. This Thing helps students visualize this rule by dividing the Normal Distribution into pieces representing each standard deviation. The first two pieces cover 68%, the next two add 27%, and all six total 99.7%. Note that the remaining 0.3% is too thin to print effectively, so these pieces are rotated and packed together for a single print. This model was crafted using MasterCAM software, which typically programs numerically controlled mills and lathes, with the equation y = exp(-0.5x^2) / sqrt(2 * pi) shaping the Normal Distribution curve.