Zehn Mark I

Zehn Mark I
Originally uploaded by Arenamontanus

Here's an old German 10 mark note, with a picture of Carl Gauss on it (as in Gaussian, as in normal distribution). To the left of the picture of Gauss is a normal distribution, with the formula.

You can read more about the distribution (and see a larger version of the formula) at Wikipedia http://en.wikipedia.org/wiki/Gaussian_distribution.