TS 2756-4

TS 2756-4 is a withdrawn standard in the acceptance-sampling family that addresses sampling procedures and charts for inspection by variables when the decision basis is percent nonconforming. The title and scope show that the document is about evaluating a lot through measured characteristics rather than by simple conforming/nonconforming counts.

What inspection by variables means

In general technical terms, a variable characteristic is a measurable quantity such as a dimension, mass, thickness, strength, or another numerical property. Because measured values vary naturally, the distribution of results can be used to estimate the proportion of units that do not meet a requirement. This differs from attribute inspection, where items are simply counted as conforming or nonconforming. Variable-based methods are especially useful when the process spread carries important quality information.

Where this standard sits in practice

The supplied scope explicitly states that the standard covers sampling procedures for inspection by variables for percent nonconforming. It does not, by itself, justify adding detailed decision rules, acceptance limits, or specific statistical formulas here. The reference to charts indicates that graphical aids are part of the method, helping users interpret sample results and connect them to lot disposition. The surrounding TS 2756 series and the cited statistical references place this document within a broader acceptance-sampling framework.

• Uses measured product characteristics as the basis for evaluation.
• Centers on percent nonconforming for lot acceptance decisions.
• Includes sampling charts to support interpretation of inspection results.
• Represents a variables-based statistical approach rather than simple attribute counting.