ISO 11843-4:2003 検出機能—パート4：検出可能な最小値を特定の値と比較するための方法論 | ページ 2

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 11843-4 was prepared by Technical Committee ISO/TC 69, Applications of statistical methods, Subcommittee SC 6, Measurement methods and results.

ISO 11843 consists of the following parts, under the general title Capability of detection:

• Part 1: Terms and definitions
• Part 2: Methodology in the linear calibration case
• Part 3: Methodology for determination of the critical value for the response variable when no calibration data are used
• Part 4: Methodology for comparing the minimum detectable value with a given value

Introduction

An ideal requirement for the capability of detection with respect to a selected state variable would be that the actual state of every observed system can be classified with certainty as either equal to or different from its basic state. However, due to systematic and random variations, this ideal requirement cannot be satisfied for the following reasons.

• a) In reality all reference states, including the basic state, are never known in absolute terms of the state variable. Hence, all states can only be characterized correctly in terms of differences from the basic state, i.e. in terms of the net state variable.
• b) In order to prevent erroneous decisions, it is generally recommended to report differences from the basic state only, i.e. data in terms of the net state variable.

• c) Furthermore, the calibration and the processes of sampling and preparation add random variation to the measurement results.

In this part of ISO 11843

• the probability is α of detecting (erroneously) that a system is not in the basic state when it is in the basic state;
• the probability is β of (erroneously) not detecting that a system, for which the value of the net state variable is equal to the minimum detectable value ( x_d) is not in the basic state.

1 Scope

This part of ISO 11843 deals with the assessment of the capability of detection of a measurement method without the assumptions in ISO 11843-2 of a linear calibration curve and certain relationships between the residual standard deviation and the value of the net state variable

Instead of estimating the minimum detectable value, this part of ISO 11843 provides

• a criterion for judging whether the minimum detectable value is less than a given level of the net state variable, and
• the basic experimental design for testing the conformity of this criterion.

For assessment of the capability of detection, for instance as part of the validation of a measurement method, it is often sufficient to confirm that the method has a minimum detectable value that is less than a given value.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 3534 (all parts), ISO 5479, ISO 5725-2, ISO 11095, ISO 11843-1 and ISO Guide 30 apply.

Bibliography