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IEC TR 63250
Edition 1.0 2021-06
TECHNICAL
REPORT
Household and similar electrical appliances – Method of measuring
performance – Assessment of repeatability, reproducibility and uncertainty
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IEC TR 63250
Edition 1.0 2021-06
TECHNICAL
REPORT
Household and similar electrical appliances – Method of measuring
performance – Assessment of repeatability, reproducibility and uncertainty
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 97.030 ISBN 978-2-8322-9939-5
– 2 – IEC TR 63250:2021 © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Determination of standard deviations . 10
4.1 General . 10
4.2 Repeatability standard deviation . 10
4.3 Reproducibility standard deviation . 10
5 Assessment of repeatability, reproducibility, and uncertainty of a measurement
method . 11
5.1 Purpose . 11
5.2 Requirements . 11
5.3 Expression of repeatability and reproducibility . 12
5.4.1 The importance of the uncertainty . 12
5.4.2 Methods to estimate uncertainty . 12
5.4.3 Expanded uncertainty calculation . 13
6 Scrutiny of results for consistency and outliers . 14
6.1 Purpose . 14
6.2 Graphical consistency technique (Mandel's h and k statistics) . 14
6.2.1 Inter-laboratory consistency statistic h . 14
6.2.2 Intra-laboratory consistency statistic k . 14
6.2.3 Evaluation . 14
6.3 Numerical outlier technique . 15
6.3.1 Cochran's C test . 15
6.3.2 Grubbs' test . 15
6.3.3 Evaluation . 15
7 Data to be reported for assessing the repeatability, reproducibility and uncertainty
of a test method. 16
Annex A (informative) Example of bottom-up analysis . 17
A.1 General . 17
A.2 Temperature measurement system . 17
A.2.1 General . 17
A.2.2 Calibration of thermocouples . 17
A.2.3 Calibration of the DAQ system . 17
A.3 Uncertainty temperature measurement . 17
A.4 Analysis of each component in the uncertainty formulation, example
thermocouple simulator . 19
Annex B (informative) Guidance on how to conduct round robin tests for household
and similar electrical appliances . 21
B.1 General . 21
B.2 Scope . 21
B.3 Process and responsibilities . 22
B.3.1 Process . 22
B.3.2 Responsibilities . 23
B.4 Testing laboratories . 23
B.4.1 Potential laboratories . 23
B.4.2 Announcement. 23
B.4.3 Selection of laboratories . 24
B.4.4 Final list of laboratories . 24
B.5 Transportation of the product . 24
B.5.1 Logistics . 24
B.5.2 Packaging. 24
B.6 Test . 24
B.6.1 Performance of test . 24
B.6.2 Laboratory visit . 25
B.6.3 Transmission of result . 25
B.7 Analysis, report and termination . 25
B.7.1 Analysis . 25
B.7.2 Report . 25
B.7.3 Termination and publication of final external report . 26
Annex C (informative) Example of a round robin test and its analysis. 27
C.1 General . 27
C.2 Standard deviations and assessment of repeatability and reproducibility . 27
C.3 Scrutiny of results for consistency and outliers. 29
C.3.1 Example of Mandel's h and k statistics . 29
C.3.2 Example of numerical outlier test . 29
Annex D (informative) Example of expression of results . 32
Bibliography . 33
Figure 1 – Visualisation of straggler and outlier of Cochrane value . 16
Figure C.1 – Mandel's h statistics. 30
Figure C.2 – Mandel's k statistics . 31
Table A.1 – Description of uncertainty parameters . 18
Table A.2 – Measuring a temperature of −23 °C at a climate room temperature
between 16 °C to 32 °C . 19
Table A.3 – Expanded uncertainty in measured temperature (U(T), k = 2) at a room
temperature in the range of 16 °C to 32 °C and a lab temperature between 14 °C and
32 °C . 19
Table A.4 – Calibration results of the simulator . 20
Table C.1 – Measurement results . 27
Table C.2 – Standard deviations, repeatability and reproducibility . 28
Table C.3 – Mandel's h and k statistics . 29
Table C.4 – Cochran's test C and Grubbs' test G . 29
Table C.5 – Cochran's test C and Grubbs' test G summary . 30
– 4 – IEC TR 63250:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
METHOD OF MEASURING PERFORMANCE – ASSESSMENT OF
REPEATABILITY, REPRODUCIBILITY AND UNCERTAINTY
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
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with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications
...