The other day my mom asked me "Tim, how quickly is covid actually spreading", and I realized this is actually a difficult question to answer. People are used to thinking about geometric growth, the staight lines of $y = mx + b$. But the behavior of a virus in the early stage of an epidemic is close to exponential growth, $y = e^{ax}$. This demonstration uses some simple graphing and fitting to teach readers about the growth of COVID-19 in the US over the past two months.

In this demo, I will make an economist style plot from a multiple country regression. For my data I will use country level data from the seminal paper "Natural Resource Abundance and Economic Growth" by Sachs and Warner, which argued that the presence of natural resources in a country caused lower growth.

A dietary supplement marketer has organized a study to investigate the effects of their product. They had randomly assigned students take different supplements or none, then complete mental math problems as fast as they good. But did the supplements really make people smarter?