Amazon applied scientist phone interview

Not sure if this was already asked but I have phone interview coming up. How can i best prepare for the interview?

Hi! These interviews tend to have two parts, a conceptual ML learning part and a coding part. For the first part, some concepts they recently asked about include:
-what’s overfitting? what causes it? how to deal with overfitting?

  • closed form solution to linear and ridge regression? what about lasso?
  • how to improve overfitting with decision trees?
  • multiple decision trees
  • difference between random forest and gradient boosting tree?

Coding part:
-average value for each layer in a binary tree