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Decision tree
Diagram Key terms bank Y12 Software Automation Diagrams and tools
Also listed as: Decision tree (diagram)
Definition
Decision tree Y12 Software Automation Diagram
A flowchart-like model where each internal node tests a condition, branches are outcomes and leaves are decisions or predictions.
Example: Is it raining? yes: take umbrella; no: next test.
Found in: syllabus, course specifications, sample exam and familiarisation guidelines, school notes.
Decision tree (diagram) Diagrams and tools Diagram
Represents all possible combinations of decisions and their resulting actions. Each path leads to another decision or a final action.
Example: If temperature > 25 then fan on.
Found in: syllabus, course specifications, sample exam and familiarisation guidelines, school notes.
Diagram of decisions and resulting actions (also an ML model).
Where it is used in the test
Syllabus area: Y12 Software Automation Diagrams and tools.
Question types it can appear in
- Drawing: Decision tree: Draw or complete a decision tree (sample Q20, fam Q7) Decision tree (diagram): Draw or label it in the online drawing tool.
- Short answer: Define, outline or explain it and tie it to the scenario.
- Multiple choice: Pick the option that matches the definition or example.
Where it has appeared in the paper
Software Automation (Part B, C). Part letters follow each paper’s own layout.
Related past questions
- Sample exam Q20a (1 mark): Decision trees Software Automation (Part B) · 1 mark
- Sample exam Q20b (3 marks): Decision trees Software Automation (Part B) · 3 marks
- Familiarisation Q7a (1 mark): Decision trees Software Automation (Part C) · 1 mark
- Familiarisation Q7b (3 marks): Decision trees Software Automation (Part C) · 3 marks
These are the questions the flashcard set links to this term. Open each one and compare your answer with its marking criteria.
Study links
- Flashcard: Decision tree in Software Automation (Year 12) · study that set
- Flashcard: Decision tree (diagram) in Diagrams and Modelling Tools (Years 11 and 12) · study that set
- Memorise: Decision trees
- Memorise: Drawing rules: DFD, structure chart, storyboard, decision tree, class diagram, ERD
- Key terms bank entry: Decision tree
- Notes: Part 3. Where this has been examined (see ../../question_bank.md) (Software Automation (Year 12))
- Notes: Research models used by software engineers to design and analyse ML, including decision… (Software Automation (Year 12))
- Notes: Part 3. Where this has been examined (see ../../question_bank.md) (Pseudocode, flowcharts and diagram rules)
- Notes: Decision trees (Software Automation (Year 12))
How to use it in an answer
A model sentence
Diagram: “A flowchart-like model where each internal node tests a condition, branches are outcomes and leaves are decisions or predictions.” Then apply it: Is it raining? yes: take umbrella; no: next test.
In a short answer, give the definition in your own words first, then tie it to the situation in the question. Do not copy the example above unless it fits the scenario.
Command words used with it
No linked question shows the command word for this term. Across the past drawing and short answer questions in this bank the words used most are: Explain, Outline, Describe, Compare, Classify, Analyse. Check the actual word in your question.
Technique for the question types
- Drawing: Use the online drawing tool: label every symbol and arrow, use the correct symbols from the specification, and add every required item.
- Short answer: One clear point per mark, use the stimulus and course terms, and answer the command word.
- Multiple choice: Read all four options, rule out wrong ones, pick one; no penalty for guessing so never leave blank.
What the marking guidelines and feedback say
No answer can be given without inventing it.
Technique: merge branches that lead to the same outcome regardless of the answer to a question (remove redundant tests), keeping every original outcome unchanged.
Technique: merge branches that lead to the same outcome, remove tests that do not change the result.
Common mistakes
- Drawing questions (2025 HSC exam Q22): refine attributes into separate inherited classes; use appropriate class diagram symbols.
- Use the term exactly as the syllabus words it, then link it to the scenario in the question; the 2025 feedback repeatedly rewards using the stimulus.
- Answer the command word: outline gives main points only, explain gives a reason or cause, discuss gives both sides.
Related terms
Same group in the syllabus: Neural network · Linear regression · Polynomial regression · Logistic regression · K-nearest neighbour (KNN) · OOP for ML programming · Neural network code (predict) · Class diagram · Class diagram inheritance and multiplicity · Entity relationship diagram (ERD) · Storyboard · Data dictionary · Gantt chart · Process diary (log book)