
Machine Learning Practice
A decision tree’s maximum depth changes how finely it divides the data
A decision tree’s maximum depth limits its layers of questions. Compare shallow and deeper trees using held-out data rather than training fit alone.

A decision tree’s maximum depth limits its layers of questions. Compare shallow and deeper trees using held-out data rather than training fit alone.

Compare MAE and RMSE with a small prediction-error example, then choose evaluation metrics that reflect the cost of large mistakes in your application.

Stratification can preserve class proportions in a train-test split. It does not automatically balance every feature or prevent data leakage.

Macro and micro averaging answer different questions about classifier performance. Use a small example to see why class balance matters.