Description
This standard covers the calculation of precision estimates and their application to specifications. In particular, it contains definitions of relevant statistical terms (Clause 3), the procedures tobe adopted in the planning of an inter-laboratory test programme to determine the precision of a test method (Clause 4), the method of calculating the precision from the results of such a programme (Clauses 5 and 6), and the procedure to be followed in the interpretation of laboratory results in relation both to precision of the test methods and to the limits laid down in specifications (Clauses 7 to 10).
TABLE OF CONTENTS
| Content | Page |
| 1 Scope | 1 |
| 2 Normative references | 1 |
| 3 Terms and definitions | 1 |
| 4 Stages in the planning of an inter-laboratory test programme for the determination of the precision of a test method | 4 |
| 5 Inspection of inter-laboratory results for uniformity and for outliers | 6 |
| 6 Analysis of variance, calculation and expression of precision estimates | 16 |
| 7 Significance of repeatability (r) and reproducibility | 24 |
| 8 Specifications | 27 |
| 9 Quality control against specifications | 28 |
| 10 Dispute procedure | 28 |
| Annex A (normative) Determination of number of samples required | 31 |
| Annex B (informative) Derivation of equation for calculating the number of samples required | 33 |
| Annex C (normative) Notation and tests | 34 |
| Annex D (normative) Example results of test for determination of bromine number and statistical tables | 41 |
| Annex E (normative) Types of dependence and corresponding transformations | 52 |
| Annex F (normative) Weighted linear regression analysis | 57 |
| Annex G (normative) Rules for rounding off results | 66 |
| Annex H (informative) | 67 |
| Annex I (informative) Specifications that relate to a specified degree of criticality | 69 |
| Bibliography | 72 |