Quincunx Boards

WHAT'S NEW

Soft Case
To see the soft cases for the Quincunx
Click here

Hard Case
To see the hard cases for the Quincunx
Click here

Pin Block
To see the Narrow Distribution Pin Block
Click here

Audio Training Cassette
To see the Audio Training Cassette for Quincunx
Click here

Which Quincunx Should I Buy?
.About 95% of all quincunx sales now are the Model WD-7 because it not only incorporates the three gates so you can view multiple distributions at one time, but it also has the adjustable pin block which makes four different distributions.

The different distributions allow you to demonstrate variability reduction, a critical aspect to process improvement.


	Products » Statistical Training Aids/Tools » Quincunx Boards

The Normal Distribution - An Illustration of Basic Probability

The normal (or Gaussian) distribution is one of the most commonly observed and is the starting point for modeling many natural processes. It usually is found in events that are the aggregation of many smaller, but unobservable events. A good example is the motion of small particles of dust in water. When viewed in a microscope they perpetually move back and forth from the random impacts of water molecules. If one were to plot the distance traveled by dust particles over a given time interval and repeat the measurement several times, the resulting distribution would be normal. The path followed by the dust particles is referred to as Brownian motion. In this case, the movement of the dust is the aggregation of several random shocks from the water molecules.

The exhibit below illustrates a more simple process that gives rise to the familiar "bell curve" of the normal distribution. In this case balls are dropped from the top and pass through a series of pins until they hit the bottom. Once at the bottom, they stack up to record the number that have hit that point. At first there does not seem to be any pattern but after a few minutes the stacks conform to the superimposed curve.