A quincunx board starts with 1 pin on the frist row, 2 pins on the second rows, 3 pins on the third row, and so on. Multiple balls are then dropped onto the top pin. As the balls fall to the bottom, they will land into bins which are placed below the last row of pins. When counting the number of balls in each bin, one notices that there are more balls in the center bins than there are in the outer bins. Mathematically, we can notice that this distribution is a normal distribution.
There are three text fields at the top of applet. This first field specifies the number of bins at the bottom of the quincunx board. This field will only allow you to enter a number between 2 and 30, inclusive. The second text field specifies the number of balls to be dropped onto the quincunx. When ever you change the number of bins, this field will automatically be updated to be of the form 2^(number of bins). This number can be changed, but this is the minimum number of balls which should be dropped to give a good normal distribution. The third text field specifies the probability that a ball will drop to the right. All probabilities should be specified in the range from 0.0 to 1.0 inclusive.
There are 6 buttons on the right side of the applet. The "Start" buttons begins the demonstration. The "Min Speed" reduces the speed of the dropping balls to the slowest possible speed. The "Slower" button reduces the speed of the dropping balls by one speed unit. The "Faster" button increase the speed of the dropping balls by one speed unit. The "Max Speed" button increases the speed of the dropping balls to the maximum possible speed. The "Stop" button waits for the last ball dropped to reach a bin, then ends the demonstration.
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