- Intro to Dummy Variables
- The Bias-Variance Tradeoff
- Intro to Hypothesis Testing
- Why Doing Good Science is Hard
- A Few Useful Things to Know About Machine Learning
3Blue1Brown has a really awesome introduction to linear algebra video series and shows intuitively satisfying animations that really hit home a multiple of linear algebra concepts. I highly recommend watching it.
On top of that, you have some posts from yours truly.