Reformatting phone numbers to a 12-character standard would take place in which phase?

• A. Business Understanding
• B. Modeling
• C. Evaluation
• D. Data Preparation

Answer: (D)

Standardizing phone numbers to a fixed 12-character format is a data preparation task. In this phase, you clean, transform, and format raw data so it’s consistent and ready for modeling. Reformatting ensures all phone numbers share a uniform representation (for example, adding a country code, removing or standardizing punctuation, and padding to reach the same length), which helps downstream algorithms treat each value equivalently and improves feature quality.

This isn’t about understanding the business problem, choosing or building a model, or evaluating model results. Those activities belong to other phases: business understanding defines goals, modeling selects and applies algorithms, and evaluation assesses how well the model performs.