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 tree8 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