Z1.4

A standard published by the American National Standards Institute (ANSI) for sampling procedures and tables for inspection by attributes, commonly used in quality control.
See also: Sampling Plan, Acceptance Sampling

Z1.9

A standard published by ANSI for sampling procedures and tables for inspection by variables, used in quality control for continuous data.
See also: Variables Sampling, Z1.4

Z-chart

A graphical tool used to display cumulative data, targets, and trends over time, often used in business and quality management to monitor performance.
See also: Trend Chart, Control Chart

Zero defects

A quality management philosophy that aims for no defects in products or processes, emphasizing prevention and a commitment to doing things right the first time.
See also: Quality Assurance, Continuous Improvement

Zero Quality Control (ZQC)

A system developed by Shigeo Shingo that focuses on preventing defects through source inspection and mistake-proofing (poka-yoke) rather than relying on inspection after the fact.
See also: Poka-Yoke, Error Proofing