EN ISO 18391:2016

European foreword
Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Rules for establishing a population specification
5 Symbol used to specify a population specification
6 Rules for indicating a population specification
Annex A (informative) - Relation in the GPS matrix model
Bibliography

ISO 18391:2016 defines rules to establish and to indicate population specifications, which are used to specify conditions on population characteristics, which are established from a set of characteristic values obtained one on each workpiece of a population of workpieces.A population specification (as applied to a population of workpieces considered as a collection and not as individual items) can be seen as a complementary requirement to the individual specification (as applied to each workpiece considered as individual items). Population specifications express the statistical hypotheses used on the population of workpieces.NOTE 1 A population specification is a complement to an individual GPS specification.NOTE 2 ISO 18391:2016 is not intended to mandate a given tolerancing method or how to calculate tolerance values. Its intent is to specify tools to allow the expression of population specifications.