ASTM E29-13
(Practice)Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
ABSTRACT
This practice is intended to assist the various technical committees in the use of uniform methods of indicating the number of digits which are to be considered significant in specification limits, for example, specified maximum values and specified minimum values. Its aim is to outline methods which should aid in clarifying the intended meaning of specification limits with which observed values or calculated test results are compared in determining conformance with specifications. Two commonly accepted methods of rounding data, identified as the absolute method and the rounding method are described. The guidelines for retaining significant figures in calculation and reporting of test results are presented in details.
SCOPE
1.1 This practice is intended to assist the various technical committees in the use of uniform methods of indicating the number of digits which are to be considered significant in specification limits, for example, specified maximum values and specified minimum values. Its aim is to outline methods which should aid in clarifying the intended meaning of specification limits with which observed values or calculated test results are compared in determining conformance with specifications.
1.2 This practice is intended to be used in determining conformance with specifications when the applicable ASTM specifications or standards make direct reference to this practice.
1.3 Reference to this practice is valid only when a choice of method has been indicated, that is, either absolute method or rounding method.
1.4 The system of units for this practice is not specified. Dimensional quantities in the practice are presented only as illustrations of calculation methods. The examples are not binding on products or test methods treated.
1.5 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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Designation:E29 −13 An American National Standard
Standard Practice for
Using Significant Digits in Test Data to Determine
1
Conformance with Specifications
ThisstandardisissuedunderthefixeddesignationE29;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope* ASTM Test Methods
E456Terminology Relating to Quality and Statistics
1.1 This practice is intended to assist the various technical
E2282Guide for Defining the Test Result of a Test Method
committees in the use of uniform methods of indicating the
IEEE/ASTMSI10Standard for Use of the International
number of digits which are to be considered significant in
System of Units (SI): The Modern Metric System
specification limits, for example, specified maximum values
and specified minimum values. Its aim is to outline methods
3. Terminology
which should aid in clarifying the intended meaning of
specification limits with which observed values or calculated
3.1 Definitions—Terminology E456 provides a more exten-
test results are compared in determining conformance with
sive list of terms in E11 standards.
specifications.
3.1.1 observed value, n—the value obtained by making an
1.2 This practice is intended to be used in determining observation. E2282
conformance with specifications when the applicable ASTM
3.1.2 repeatability conditions, n—conditions where inde-
specifications or standards make direct reference to this prac-
pendent test results are obtained with the same method on
tice.
identicaltestitemsinthesamelaboratorybythesameoperator
1.3 Referencetothispracticeisvalidonlywhenachoiceof
using the same equipment within short intervals of time. E177
method has been indicated, that is, either absolute method or
3.1.3 repeatability standard deviation (s ), n—the standard
r
rounding method.
deviation of test results obtained under repeatability
1.4 The system of units for this practice is not speci-
conditions. E177
fied. Dimensional quantities in the practice are presented only
3.1.4 significant digit—any of the figures 0 through 9 that is
as illustrations of calculation methods. The examples are not
used with its place value to denote a numerical quantity to
binding on products or test methods treated.
some desired approximation, excepting all leading zeros and
1.5 This standard does not purport to address all of the
some trailing zeros in numbers not represented with a decimal
safety concerns, if any, associated with its use. It is the
point.
responsibility of the user of this standard to establish appro-
3.1.4.1 Discussion—This definition of significant digits re-
priate safety and health practices and determine the applica-
lates to how the number is represented as a decimal. It should
bility of regulatory limitations prior to use.
not be inferred that a measurement value is precise to the
number of significant digits used to represent it.
2. Referenced Documents
2
3.1.4.2 Discussion—The digit zero may either indicate a
2.1 ASTM Standards:
specific value or indicate place only. Zeros leading the first
E177Practice for Use of the Terms Precision and Bias in
nonzerodigitofanumberindicateorderofmagnitudeonlyand
are not significant digits. For example, the number 0.0034 has
1
ThispracticeisunderthejurisdictionofASTMCommitteeE11onQualityand two significant digits. Zeros trailing the last nonzero digit for
Statistics and is the direct responsibility of Subcommittee E11.30 on Statistical
numbersrepresentedwithadecimalpointaresignificantdigits.
Quality Control.
For example, the numbers 1270. and 32.00 each have four
Current edition approved Aug. 1, 2013. Published August 2013. Originally
significantdigits.Thesignificanceoftrailingzerosfornumbers
approved in 1940. Last previous edition approved in 2008 as E29–08. DOI:
10.1520/E0029-13.
represented without use of a decimal point can only be
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
identified from knowledge of the source of the value. For
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
example, a modulus strength, stated as 140000 Pa, may have
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. as few as two or as many as six significant digits.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E29−13
3.1.4.3 Discussion—To eliminate ambiguity, the exponen- mining conformance with specifications
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E29 − 08 E29 − 13 An American National Standard
Standard Practice for
Using Significant Digits in Test Data to Determine
1
Conformance with Specifications
This standard is issued under the fixed designation E29; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope*
1.1 This practice is intended to assist the various technical committees in the use of uniform methods of indicating the number
of digits which are to be considered significant in specification limits, for example, specified maximum values and specified
minimum values. Its aim is to outline methods which should aid in clarifying the intended meaning of specification limits with
which observed values or calculated test results are compared in determining conformance with specifications.
1.2 This practice is intended to be used in determining conformance with specifications when the applicable ASTM
specifications or standards make direct reference to this practice.
1.3 Reference to this practice is valid only when a choice of method has been indicated, that is, either absolute method or
rounding method.
1.4 The system of units for this practice is not specified. Dimensional quantities in the practice are presented only as illustrations
of calculation methods. The examples are not binding on products or test methods treated.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
E2282 Guide for Defining the Test Result of a Test Method
IEEE/ASTM SI 10 Standard for Use of the International System of Units (SI): The Modern Metric System
3. Terminology
3.1 Definitions:DefinitionsTerminology—Terminology E456 provides a more extensive list of terms in E11 standards.
3.1.1 observed value, n—the value obtained by making an observation. E2282
3.1.2 repeatability conditions, n—conditions where independent test results are obtained with the same method on identical test
items in the same laboratory by the same operator using the same equipment within short intervals of time. E177
3.1.3 repeatability standard deviation (s ), n—the standard deviation of test results obtained under repeatability conditions.
r
E177
3.1.4 significant digit—any of the figures 0 through 9 that is used with its place value to denote a numerical quantity to some
desired approximation, excepting all leading zeros and some trailing zeros in numbers not represented with a decimal point.
1
This practice is under the jurisdiction of ASTM Committee E11 on Quality and Statistics and is the direct responsibility of Subcommittee E11.30 on Statistical Quality
Control.
Current edition approved Oct. 1, 2008Aug. 1, 2013. Published October 2008August 2013. Originally approved in 1940. Last previous edition approved in 20062008 as
E29 – 06b.E29 – 08. DOI: 10.1520/E0029-08.10.1520/E0029-13.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3.1.4.1 Discussion—
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E29 − 13
This definition of significant digits relates to how the number is represented as a decimal. It should not be inferred that a
measurement value is precise to the number of significant digits used to represent it.
3.1.4.2 Discussion—
The digit zero may either indicate a specific value or indicate place only. Zeros leading the first nonzero digit of a number indicate
order of magnitude only and are not significant digits. For example, the number 0.0034 has two significant digits. Zeros trailing
the last nonzero digit for numbers represented with a decimal
...
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