Current Slide

How to Handle Missing Data?

• Ignore the tuple: usually done when class label is missing (when doing classification)—not effective when the % of missing values per attribute varies considerably
• Fill in the missing value manually: tedious + infeasible?
• Fill in it automatically with
• a global constant : e.g., “unknown”, a new class?!
• the attribute mean
• the attribute mean for all samples belonging to the same class: smarter
• the most probable value: inference-based such as Bayesian formula or decision tree