🔥🔥 Don’t Miss Out on Our End of Autumn Sale. If you have any questions, feel free to click the bottom right corner to contact our customer service..

Concat us[email protected]
Shopping Cart

No products in the cart.

🔍
BS ISO 5725-3:1994:2002 Edition

BS ISO 5725-3:1994:2002 Edition

$167.15

Accuracy (trueness and precision) of measurement methods and results – Intermediate measures of the precision of a standard measurement method

Published By Publication Date Number of Pages
BSI 2002 38
PDF Format Searchable Printable Preview Now
Guaranteed Safe Checkout
Category:

If you have any questions, feel free to reach out to our online customer service team by clicking on the bottom right corner. We’re here to assist you 24/7.
Email:[email protected]

1.1 This part of ISO 5725 specifies four intermediate precision measures due to changes in observation conditions (time, calibration, operator and equipment) within a laboratory. These intermediate measures can be established by an experiment within a specific laboratory or by an interlaboratory experiment.

Furthermore, this part of ISO 5725

  1. discusses the implications of the definitions of intermediate precision measures;

  2. presents guidance on the interpretation and application of the estimates of intermediate precision measures in practical situations;

  3. does not provide any measure of the errors in estimating intermediate precision measures;

  4. does not concern itself with determining the trueness of the measurement method itself, but does discuss the connections between trueness and measurement conditions.

1.2 This part of ISO 5725 is concerned exclusively with measurement methods which yield measurements on a continuous scale and give a single value as the test result, although the single value may be the outcome of a calculation from a set of observations.

1.3 The essence of the determination of these intermediate precision measures is that they measure the ability of the measurement method to repeat test results under the defined conditions.

1.4 The statistical methods developed in this part of ISO 5725 rely on the premise that one can pool information from “similar” measurement conditions to obtain more accurate information on the intermediate precision measures. This premise is a powerful one as long as what is claimed as “similar” is indeed “similar”. But it is very difficult for this premise to hold when intermediate precision measures are estimated from an interlaboratory study. For example, controlling the effect of “time” or of “operator” across laboratories in such a way that they are “similar”, so that pooling information from different laboratories makes sense, is very difficult. Thus, using results from interlaboratory studies on intermediate precision measures requires caution. Within-laboratory studies also rely on this premise, but in such studies it is more likely to be realistic, because the control and knowledge of the actual effect of a factor is then more within reach of the analyst.

1.5 There exist other techniques besides the ones described in this part of ISO 5725 to estimate and to verify intermediate precision measures within a laboratory, for example, control charts (see ISO 5725‑6). This part of ISO 5725 does not claim to describe the only approach to the estimation of intermediate precision measures within a specific laboratory.

NOTE 1 This part of ISO 5725 refers to designs of experiments such as nested designs. Some basic information is given in Annex B and Annex C. Other references in this area are given in Annex E.

PDF Catalog

PDF Pages PDF Title
1 BRITISH STANDARD
2 Committees responsible for this British�Standard
3 Contents
9 Introduction
10 1 Scope
1.1 This part of ISO�5725 specifies four intermediate precision measures due to changes in observ…
1.2 This part of ISO�5725 is concerned exclusively with measurement methods which yield measureme…
1.3 The essence of the determination of these intermediate precision measures is that they measur…
1.4 The statistical methods developed in this part of ISO�5725 rely on the premise that one can p…
11 1.5 There exist other techniques besides the ones described in this part of ISO�5725 to estimate …
2 Normative references
3 Definitions
4 General requirement
5 Important factors
12 Table 1Four important factors and their states
6 Statistical model
6.1 Basic model
6.2 General mean, m
13 6.3
6.4
14 6.5
15 7 Choice of measurement conditions
8 Within-laboratory study and analysis of intermediate precision measures
8.1 Simplest approach
16 8.2 An alternative method
8.3 Effect of the measurement conditions on the final quoted result
17 9 Interlaboratory study and analysis of intermediate precision measures
9.1 Underlying assumptions
9.2 Simplest approach
9.3 Nested experiments
9.4 Fully-nested experiment
9.5 Staggered-nested experiment
18 Figure 1 Schematic layouts for three-factor and four-factor fully-nested experiments
Figure 2 Schematic layout of a four-factor staggered-nested experiment
9.6 Allocation of factors in a nested experimental design
19 9.7 Comparison of the nested design with the procedure given in ISO�5725-2
9.8 Comparison of fully-nested and staggered-nested experimental designs
20 Annex A (normative) Symbols and abbreviations used in ISO 5725
22 Annex B (normative) Analysis of variance for fully-nested experiments
B.1 Three-factor fully-nested experiment
Table B.1 ANOVA table for a three-factor fully-nested experiment
23 B.2 Four-factor fully-nested experiment
24 Table B.2 ANOVA table for a four-factor fully-nested experiment
25 Annex C (normative) Analysis of variance for staggered-nested experiments
C.1 Three-factor staggered-nested experiment
26 Table C.1 ANOVA table for a three-factor staggered-nested experiment
C.2 Four-factor staggered-nested experiment
27 Table C.2 ANOVA table for a four-factor staggered-nested experiment
C.3 Five-factor staggered-nested experiment
Table C.3 ANOVA table for a five-factor staggered-nested experiment
28 C.4 Six-factor staggered-nested experiment
Table C.4 ANOVA table for a six-factor staggered-nested experiment
Annex D (informative) Examples of the statistical analysis of intermediate precision experiments
D.1 Example 1 — Obtaining the [time + operator]-different intermediate precision standard deviation,
D.1.1 Background
29 D.1.2 Analysis
Table D.1 Original data — Carbon content,
30 Figure D.1 Carbon content in steel — Deviations from the mean of the measurements on both days versus the sa…
31 D.2 Example 2 — Obtaining the time-different intermediate precision standard deviation by interlabora…
D.2.1 Background
D.2.2 Analysis
32 Figure D.2 Vanadium content in steel — Test results for day 1 and 2 at level 1 versus laboratory number
33 Table D.2 Original data — Vanadium content, % (
34 Tab;e D.3
35 Table D.4 ANOVA table — Vanadium content
Table D.5
36 Figure D.3 Vanadium content in steel — Repeatability standard deviation
37 Annex E (informative) Bibliography

Related products

BS ISO 5725-3:1994
$167.15