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ASTM E 177 : 1990 : REV A : R2002

Superseded

Superseded

A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.

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Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods

Available format(s)

Hardcopy , PDF

Superseded date

11-11-2014

Superseded by

ASTM E 177 : 2004

Language(s)

English

Published date

10-01-2002

€74.48
Excluding VAT

Committee
E 11
DocumentType
Standard Practice
Pages
12
ProductNote
Reconfirmed 2002
PublisherName
American Society for Testing and Materials
Status
Superseded
SupersededBy
Supersedes

1.1 The purpose of this practice is to present concepts necessary to the understanding of the terms "precision" and "bias" as used in quantitative test methods. This practice also describes methods of expressing precision and bias and, in a final section, gives examples of how statements on precision and bias may be written for ASTM test methods. The term "accuracy", used in earlier editions of Practice E 177, embraces both precision and bias (see Section 20 and Note 4).

1.2 Informal descriptions of the concepts are introduced in the text as the concepts are developed, and appear in the following sections:

<
Section
Terminology3
Significance and Use4

GENERAL CONCEPTS

Test Method5
Measurement Terminology6
Observation7
Test Determination8
Test Result9

SOURCES OF VARIABILITY

Experimental Realization of a Test Method10
Operator 11
Apparatus 12
Environment 13
Sample 14
Time 15

STATISTICAL CONCEPTS

Accepted Reference Value 16
Statistical Control 17
Precision 18
Bias 19
Accuracy 20
Variation of Precision and Bias with Material21
Variation of Precision and Bias with Sources of Variability22

COMBINATIONS OF SOURCES OF VARIABILITY

Repeatability and Laboratory Bias 23
Other Within-a-Single Laboratory Precisions24
Reproducibility and Bias of the Test Method25
Range of Materials 26

METHODS OF EXPRESSING PRECISION AND BIAS

Indexes of Precision 27
Preferred Indexes of Precision for ASTM Test Methods 28
Preferred Statements of Bias for ASTM Test Methods 29
Elements of a Statement of Precision and Bias 30

STATEMENTS OF PRECISION AND BIAS

Examples of Statements of Precision and Bias31

APPENDIX
Alphabetical List of Descriptions of Terms from the Text X1

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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