Decision Trees

• A standard way to model a process is a decision tree.
• You start at the top, where the top node has a question.
• Each possible answer has a branch, and depending on the answer you follow the branch.
• The leaves have answers.
• Here's a decsion tree from the December 2003 exam:

• Submit Exam	-no->	Q
  yes
  Submit Coursework	-no->	Q
  yes
  Pass Exam	-no->	lower(CW,Exam)
  yes
  Pass Coursework	-no->	lower(CW,Exam)
  yes
  average(Coursework,Exam)

• It's easy to do this with a rule based system.
• The first rule will take one branch of the first question
• The rules for the second and lower tiers will include all of the answers from above.
• Your rules can be more brief if the questions are only asked when needed.