Last week I taught a class on design of experiments to a biotech company in Leiden, Netherlands. Afterwards I spent a few days in Utrecht with some friends from Germany. Imagine my excitement (nerd alert!) when on my first walk from our hotel to the city center just a few hundred feet down the sidewalk I encountered this mural featuring a differential equation.

Not being a physicist, I did not immediately grasp the formula’s importance, nor the clue provided by the fellow high-stepping down a street. It turns out this fellow is a drunk whose walk has become random. The mural, as explained by Utrecht University, pays homage to their famous professor Leonard Ornstein who, in the early 1900s along with another physicist—George Uhlenbeck—developed an important variant of the “random walk”—a term introduced by pioneering statistician Karl Pearson. The Ornstein-Uhlenbeck process is used to derive models from “big” financial data, including inflation rates, commodity prices and stock values.

I did not expect to gain an education on a vacation expedition.

Very cool!

PS: I thought about asking my colleague Martin Bezener, a PhD statistician, for his opinion on the chances of coming across something so relevant to our mission at Stat-Ease while on a random walk. But I will not bother, because I already know what he would say: “One-hundred percent: It already happened”.