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Working with Data

Numerical Data at Scale

8 min+70 XPStep 1/11

One feature shouldn't outshout the rest

Picture a dataset with two features: age (0–100) and income (0–1,000,000). To the model, every unit counts the same — so a $1 change in income looks identical to a 1-year change in age, and income's huge range lets it dominate every gradient step.

Normalization rescales features onto a common footing so no column bullies the rest. Two workhorses:

  • Min-max scaling squashes everything into the range 0 to 1
  • Z-score standardization recenters each feature around a mean of 0 with a spread of 1

After scaling, the model compares features on their merits — not their units.

analogy

Think of features as voters. Without normalization, the loudest voice wins regardless of wisdom. Scaling hands everyone the same-size megaphone.