ASTM G117-98

Standard Guide for Calculating and Reporting Measures of Precision Using Data from Interlaboratory Wear or Erosion Tests

SCOPE
1.1 This guide offers direction on the handling of data from interlaboratory tests for wear or erosion. It describes a format for entering data and for subsequently reporting results on measures of precision in a Committee G-2 standard. It indicates methods for calculation of the needed statistical quantities.
1.2 The document offers guidance based on a Committee G-2 consensus, and exists for the purpose of emphasizing the need to use established statistical practices, and to introduce more uniformity in reporting interlaboratory test results in Committee G-2 standards.
1.3 An example of how the methods described in this guide may be applied is available in personal computer format (DOS type system) on 5.25-in. floppy disk as a spreadsheet (LOTUS, rel. 2) file. The purpose is to facilitate use of the methods in this guide. The example file contains all needed equations in the recommended format and can be edited to accept new data. ASTM Headquarters or the Chairman of G-2 should be contacted for a copy of that computer file. The user must have spreadsheet software (for example, LOTUS or compatible) available.
1.4 The methods used in this document are consistent with Practices E691 and E177, and with the PC version of Practice E691.

General Information

• Status: Historical
• Publication Date: 09-Apr-1998
• ICS: 17.040.20 - Properties of surfaces
• ICS: 19.060 - Mechanical testing
• Technical Committee: G02 - Wear and Erosion

Relations

• Replaced By: ASTM G117-02 - Standard Guide for Calculating and Reporting Measures of Precision Using Data from Interlaboratory Wear or Erosion Tests
• Effective Date: 10-Nov-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn. Contact ASTM International (www.astm.org) for the latest information.
Designation: G 117 – 98
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Guide for
Calculating and Reporting Measures of Precision Using
1
Data from Interlaboratory Wear or Erosion Tests
This standard is issued under the fixed designation G 117; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope G 77 Test Method for Ranking Resistance of Materials to
4
Sliding Wear Using Block-on-Ring Wear Test
1.1 This guide offers direction on the handling of data from
interlaboratory tests for wear or erosion. It describes a format
3. Summary of Guide
for entering data and for subsequently reporting results on
3.1 Use of this guide in preparation of interlaboratory test
measures of precision in a Committee G-2 standard. It indi-
results for inclusion in G-2 standards involves a sequence of
cates methods for calculation of the needed statistical quanti-
steps. First the raw data from the individual laboratories are
ties.
entered into a table of any suitable form that permits calcula-
1.2 The document offers guidance based on a Committee
tion of average values and standard deviations for each
G-2 consensus, and exists for the purpose of emphasizing the
laboratory. Then those two measures are entered, for each
need to use established statistical practices, and to introduce
laboratory, into a table such as that shown in Fig. 1. Then the
more uniformity in reporting interlaboratory test results in
steps described in this guide are carried out, leading to
Committee G-2 standards.
calculation of the precision measures that are to be used in the
1.3 An example of how the methods described in this guide
standard being prepared.
may be applied is available in personal computer format (DOS
type system) on floppy disk as a spreadsheet (LOTUS, rel. 4)
4. Significance and Use
file. The purpose is to facilitate use of the methods in this
4.1 This guide is intended to assist in developing statements
guide. The example file contains all needed equations in the
of precision and supporting data that will be used in Committee
recommended format and can be edited to accept new data.
G-2 standards. The methods and approach are drawn from
ASTM Headquarters or the Chairman of G-2 should be
Practice E 177 and E 691. It was felt that preparation of this
contacted for a copy of that computer file. The user must have
guide and its use in Committee G-2 would lead to appropriate
spreadsheet software (for example, LOTUS or compatible)
statistical analyses and more uniformity in G-2 standards
available.
regarding reporting of interlaboratory results and precision.
1.4 The methods used in this document are consistent with
The guide is not meant to substitute for possible use of
Practices E 691 and E 177, and with the PC version of Practice
2 Practices E 177 or E 691 in developing committee standards.
E 691.
5. Procedure
2. Referenced Documents
5.1 An example of interlaboratory data analyzed and pre-
2.1 ASTM Standards:
sented in the recommended format is shown in Fig. 1. The data
E 177 Practice for Use of the Terms Precision and Bias in
were obtained from an interlaboratory series of solid particle
3
ASTM Test Methods
erosion tests carried out in connection with Practice G 76. This
E 691 Practice for Conducting an Interlaboratory Study to
table format can be used with either PC spreadsheet calculation
3
Determine the Precision of a Test Method
or hand calculation.
G 65 Test Method for Measuring Abrasion Using the Dry
5.2 Data tabulation and calculation can be carried out by use
4
Sand/Rubber Wheel Apparatus
of a PC and numeric spreadsheet software (for example,
G 76 Practice for Conducting Erosion Tests by Solid Par-
LOTUS), as described in Table 1, or by any other appropriate
4
ticle Impingement Using Gas Jets
means such as hand calculation (Table 2). The formulae were
obtained from Practices E 177 or E 691 or from statistical
1
This guide is under the jurisdiction of ASTM Committee G-2 on Wear and
analysis texts. Formulae that are used for calculation are given
Erosion and is the direct responsibility of Subcommittee G02.2 on Computerization
in Table 1 for spreadsheet calculation (for example, LOTUS)
in Wear and Erosion.
Current edition approved Apr. 10, 1998. Published October 1998 Originally and in Table 2 for hand calculation.
published as G 117 – 93. Last previous edition G 117 – 93.
5.3 The sequence of steps in assembling and handling the
2
Available from ASTM Headquarters. Order PCN 12-506910-34.
data is as follows (re
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