Decision Tree Generalisation

• So how well does a decision tree generalise.
• If the tree covers the entire possible input space, it will give an answer.
• Of course the question is how well does it perform.
• It is generally a quick answer.
• You can omit features.
• How well does our tree work?
• 

• Colour	Size	Act	Age	Category/Inflated
  YELLOW	SMALL	STRETCH	ADULT	T
  YELLOW	SMALL	STRETCH	CHILD	F
  YELLOW	SMALL	DIP	ADULT	F
  YELLOW	SMALL	DIP	CHILD	F
  YELLOW	LARGE	STRETCH	ADULT	T
  YELLOW	LARGE	STRETCH	ADULT	T
  YELLOW	LARGE	STRETCH	CHILD	F
  YELLOW	LARGE	DIP	ADULT	F
  YELLOW	LARGE	DIP	CHILD	F
  PURPLE	SMALL	STRETCH	ADULT	T
  PURPLE	SMALL	STRETCH	ADULT	T
  PURPLE	SMALL	STRETCH	CHILD	F
  PURPLE	SMALL	DIP	ADULT	F
  PURPLE	SMALL	DIP	CHILD	F
  PURPLE	LARGE	STRETCH	ADULT	T
  PURPLE	LARGE	STRETCH	ADULT	T
  PURPLE	LARGE	STRETCH	CHILD	F
  PURPLE	LARGE	DIP	ADULT	F
  PURPLE	LARGE	DIP	CHILD	F

• You aren't usually going to get perfect answers. This is a really simple (almost rigged) example.