Module · Decision Trees✅Knowledge checkCheck: choosing a question, and stopping4 questions · Pass at 60%1. Of twenty-four films, the question that splits them a perfect 12 and 12 removes 0.000 impurity. What was wrong with picking the evenest split?Nothing — an even split is always the best availableEven splits are good but this table was unusualEvenness says nothing about whether each side agrees about the outcomeThe split should have been 10 and 14 to match the star question2. On all 24 films, 'is it a sequel?' beats 'did it open on 3,000 screens?'. On the ten films with a star, the ranking reverses. What does that establish?One of the two measurements must be wrongA tree is not a ranked list of features — a question's worth depends on which rows are still in front of itThe star question should not have been asked firstThe two questions are measuring the same thing3. Grown with no floor, the tree got 23 of 24 right, with 7 of its 12 leaves holding a single film. What is the objection?A leaf holding one film has written down an answer rather than found a pattern23 of 24 is too low for a table this smallThe tree should have been able to get all 24Twelve leaves is too few for twenty-four films4. Two films answer all five questions identically and one was a hit. What should the tree do about them?Grow deeper until it separates themDrop both films from the tableNothing: a tree cannot be more certain than its questions allowAdd a random column so a split becomes possibleCheck answers← Back to Decision TreesNext topic →
