Few Hr calls prior and between. First round: Probability questions, questions on general ml knowledge: lasso, ridge, mathematical justification of gradient descent, prob inequalities, linear algebra and geometric interpretations of probability. Final Onsite: Leetcode problems, stats, harder probability problems, deeper into ml knowledge: linear regression basics, pca, linear algebra, questions on the classes you have taken. ML knowledge is very much needed.

interviewed with low-mid frequency equity team. 1st round: coding + statistics, mainly probability, stochastics and OLS. Questions are quite interesting. 2nd round: only about past experience, focus on all the details. 3rd round: onsite interview.