Scatter diagrams plot (x,y) pairs. Visual representation shows relationship type. Patterns: (1) Positive: points trend upward (increasing x, increasing y); (2) Negative: points trend downward; (3) No correlation: random scatter; (4) Non-linear: curved pattern. Strength: Points close to line = strong; scattered = weak. Example: Height vs shoe size (positive correlation). Age vs income (positive with scatter). Temperature vs ice cream sales (positive). Drawing: Plot x-axis, y-axis. Mark each (x,y). Interpret pattern. Solving: Identify relationship direction. Estimate correlation strength. Exam tip: Use before calculating correlation. Recognize outliers visually. Practice: Various scatter plot scenarios.