Data Discretization

Can be used to turn numerical data into Categorical Data by creating intervals which replace the actual raw data values.

Advantages are:

• reduced data size
• can make some numerical attributes comparable

**Split (top-down) **

• split data into intervals which can be seen as one value

Merge (bottom-up)

• merge data until it becomes a “bigger chunk”

Methods

• Binning → Unsupervised and top-down split
• Histogram Analysis → Unsupervised and top-down split
• Clustering → Unsupervised and top-down split or bottom-up merge
• Decision-tree analysis → Supervised and top-down split
• Correlation Analysis → e.g. Chi-Squared Test → Unsupervised and bottom-up merge