Posts by Pablo Vena

Heteroscedastic Bayesian Robust Regression

The PyMC gallery has two robust regression notebooks: one with a Student-t likelihood (pymc-examples:GLM-robust) and one with the Hogg (2010) signal-vs-noise mixture (pymc-examples:GLM-robust-with-outlier-detection). Both protect against vertical outliers (points with unusual response values), but neither defends against leverage points: observations far from the bulk of the predictor space, which can drag the regression line even under a heavy-tailed likelihood.

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