AS 4595-1999

1 - AS 4595-1999 COPPER, LEAD AND ZINC SULFIDE CONCENTRATES-PRECISION AND BIAS OF MASS MEASUREMENT TECHNIQUES
4 - PREFACE
5 - CONTENTS
7 - 1 Scope
7 - 2 Normative references
8 - 3 Definitions
8 - 3.1 accuracy:
8 - 3.2 Bias:
8 - 3.3 Student’s t-value;
8 - 3.4 Bias Detection Limit;
8 - 3.5 Type I risk;
8 - 3.6 Type II risk;
9 - 3.7 Probable Bias Range;
9 - 3.8 Precision:
9 - 3.9 variance;
9 - 3.10 standard deviation;
9 - 3.11 relative standard deviation;
9 - 3.12 Coefficient of Variation;
9 - 3.13 Confidence Interval;
9 - 3.14 Confidence Range;
9 - 3.15 correlation coefficient;
9 - 3.16 draft survey:
9 - 3.17 belt scale:
10 - 3.18 static scale:
10 - 4 General remarks
10 - 4.1 Draft surveys
11 - 4.2 Belt scales
12 - 4.3 Weighbridges
12 - 4.4 Hopper scales
13 - 4.5 Gantry scales
13 - 4.6 Platform scales
14 - 5 Certified weights
14 - 6 Methods of operation
14 - 6.1 General
15 - 6.2 Draft surveys
15 - 6.2.1 Draft surveys at loading and discharge
17 - 6.2.2 Draft survey versus weighbridge
19 - 6.3 Belt scales
22 - 6.4 Weighbridges
24 - 6.5 Hopper scales
25 - 6.6 Gantry scales
27 - 6.7 Platform scales
30 - Annex A - Tables
40 - Annex B - Statistics
40 - B.1 Terms and symbols
40 - B.2 Measure for central tendency
41 - B.3 Measures for variability
43 - B.4 Measures for precision
44 - B.5 Central Limit Theorem
44 - B.6 Student’s t-test
46 - B.7 Bias Detection Limits
47 - B.8 Probable Bias Ranges
48 - B.9 Correlation-regression
50 - Annex C - Draft surveys
52 - Annex D - Bibliography

Sets out guidelines to test for bias over a wide range of mass measurement techniques, to estimate the precision for each technique and to calculate the precision for wet mass when estimated by one of those techniques. This Standard is identical with and has been reproduced from ISO 12745:1996.

This International Standard provides guidelines to test for bias over a wide range of mass measurement techniques, to estimate the precision for each technique, and to calculate the precision for wet mass when estimated by applying one of these techniques.The guidelines are based on the application of statistical tests to verify that a mass measurement technique is unbiased, to estimate the variance as the most basic measure for its precision and to check the linearity of a static scale over its working range. Calibration methods and performance tests for compliance with applicable regulations generate test results that can be used to quantify precision and bias for each of these mass measurement techniques and to verify linearity for static weighing devices.The guidelines apply to mass measurement techniques used to estimate the wet mass for cargoes or shipments of mineral concentrate as the basis for freight and insurance charges and for preliminary payments or for final settlements between trading partners.The application of static scales requires that at least one certified weight with a mass of no less than one (1) tonne be either available on location or brought in for calibration purposes, and that this certified weight be applicable to the scale in accordance with the manufacturer's recommendations. A set of certified weights covering the entire working range of a weighing device simplifies the process of verifying its state of calibration, estimating its precision as a function of applied load and testing its linearity over the working range.

First published as AS 4595-1999.