# Math and Science Links Dec 2021

As one of my college classmates said, when I entered college, I thought I knew 10% of all the math in the world. Four years and 17 classes later, I thought I knew 1% of all the math in the world. Then I went to grad school, and now I only think I know 0.1%. The more you climb, the better you can see all the mountains you haven’t visited yet.

The upside is that there’s always cool stuff to learn. Like **convolution**! I barely saw it in college somehow, but this article helped me understand it, as it says, intuitively.

This visualization of **linear regression** using coiled springs is also really cool! I had never seen before that an outlier at an end of a distribution mostly affects slope, while an outlier in the middle mostly affects intercept. But springs make that clear.

The **Gini coefficient** is a clever way of measuring inequality or market concentration. But you have to be careful with it, because it’s also pretty crude.

Moving to physics, you might recall from Drug Age I that I’m fascinated by quantum mechanics but have never really learned it properly. So here’s links to a book review on **double-slit experiments** and a Wikipedia article on **phase shift experiments** that I haven’t mastered and find beautiful and grotesque. Seriously, what the heck is going on in this world?