MACHINE-LEARNING REQUIREMENT
                                │
                                ▼
                   Do historical rows contain
                     a known correct outcome?
                        │               │
                       YES              NO
                        │               │
                        ▼               ▼
               SUPERVISED LEARNING   Is the system taking
                        │            sequential actions and
             ┌──────────┴─────────┐   receiving rewards?
             │                    │          │          │
             ▼                    ▼         YES         NO
       Predict category     Predict number   │           │
             │                    │          ▼           ▼
     CLASSIFICATION          REGRESSION  REINFORCEMENT  UNSUPERVISED
             │                              LEARNING      LEARNING
      ┌──────┴──────┐                                      │
      │             │                                      ▼
  Two classes   3+ classes                           Find structure,
      │             │                                similarity or groups
      ▼             ▼                                      │
   BINARY       MULTICLASS                                  ▼
 CLASSIFICATION CLASSIFICATION                          CLUSTERING
Quick selector:
Known answer?                  → Supervised
Known category?                → Classification
Known numeric outcome?         → Regression
No label, discover groups?     → Clustering
Sequential actions + rewards?  → Reinforcement learning