Diagnose and fix linear regression violations

Role: Data Scientist

Category: Statistics & Math

Difficulty: medium

Interview Round: Onsite

Quick Answer: This question evaluates mastery of linear regression diagnostics and inference, including Gauss–Markov assumptions and their role for BLUE versus hypothesis testing, OLS residual properties and orthogonality, multicollinearity and VIF, the effects of predictor scaling, and robustness to heavy tails and heteroskedasticity.