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A point outside control limits (typically ±3σ) is a classic, high-confidence indicator of special-cause variation—something changed beyond normal process noise—triggering investigation and corrective action. Patterns entirely within limits can also signal special causes (Western Electric rules), such as a run of many points on one side of the mean, trends of consecutive increases/decreases, or clustering in zones near limits; however, a single point beyond a control limit is the clearest, least ambiguous trigger. Random zig-zag (Option B) without rule violations generally reflects common-cause variation. Two near-limit points (Option C) may be suspicious, but by itself is not a definitive rule unless combined with additional points (e.g., 2 of 3 in zone A). Mild drift around the mean (Option D) may be normal unless it forms a defined trend rule. CAPM quality control stresses distinguishing process control (common causes) from capability (meeting specs). After detecting special cause, teams should identify root causes, implement corrective actions, and then monitor to confirm the process returns to statistical control.