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Elements and Performance Criteria

1. Identify the measured quantity and the uncertainty components
   • Specify an equation for the measurement
   • List uncertainty components that are associated with each input in the equation
2. Determine the size of each uncertainty component
   • Calculate the standard deviations and standard deviation of the mean from the measurement results
   • Use calibration reports, manufacturer's specifications, quality control and validation data, and experimental data to collect other available information on the uncertainty components
3. Reduce each uncertainty component to a standard uncertainty
   • Allocate an appropriate distribution for each uncertainty component
   • Calculate the standard uncertainties
4. Calculate an expanded uncertainty to the required confidence level
   • Calculate the sensitivity coefficient for each uncertainty component
   • Calculate a combined standard uncertainty
   • Determine an appropriate coverage factor based on the degrees of freedom associated with each uncertainty component
   • Calculate the expanded uncertainty
5. Report the expanded uncertainty
   • Report the result and uncertainty to an appropriate number of significant figures
   • Report the confidence level and coverage factor
   • Determine the appropriateness of the size of the expanded uncertainty relative to the tolerance or required accuracy of the test
   • Determine the fitness for purpose of the expanded uncertainty relative to the use of the measurement result

Range Statement

This field allows for different work environments and conditions that may affect performance. Essential operating conditions that may be present (depending on the work situation, needs of the candidate, accessibility of the item, and local industry and regional contexts) are included.
Standards, codes, procedures and/or workplace requirements	Standards, codes, procedures and/or enterprise requirements include the latest version of one or more of: Australian and international standards and guides, such as: competency requirements for testing and calibration laboratories, quality management and measurement management ISO 5725 Accuracy (trueness and precision) of measurement methods and results ISO/IEC Guide 98-3:2008 Uncertainty of Measurement - Part 3 Guide to the Expression of Uncertainty in Measurement Eurachem/CITAC Guide CG4 Quantifying uncertainty in analytical measurement, Eurolab technical report and Nordtest National Association of Testing Authorities (NATA) accreditation program requirements and NATA technical notes national measurement regulations and guidelines Australian codes, such as of good manufacturing practice for medicinal products (GMP), and principles of good laboratory practice (GLP) workplace documents, such as quality manual, customer quality plan, equipment manuals and warranty, supplier catalogues and handbooks validated sampling and test procedures
Data	Data includes: worksheets, spreadsheets or databases linked to information management systems the results of tests, measurements and analyses
Records	Records include information associated with one or more of: purchase of equipment and materials and service records manufacturer datasheets calibration reports history of calibration and test results
Work health and safety (OHS) and environmental management requirements	WHS and environmental management requirements include: · complying with WHS and environmental management requirements at all times, which may be imposed through state/territory or federal legislation. These requirements must not be compromised at any time · applying standard precautions relating to the potentially hazardous nature of samples accessing and applying current industry understanding of infection control issued by the National Health and Medical Research Council (NHMRC) and State and Territory Departments of Health, where relevant

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Performance Evidence

Evidence of competence in this unit must satisfy all of the requirements of the elements and performance criteria, and include demonstration of:

using scientific notation, correct units and correct number of significant figures

evaluating formulae containing powers, exponents and logarithms functions

preparing and interpreting linear graphs

using statistical analysis to estimate and report measurement uncertainty in accordance with the ISOGuide to the Expression of Uncertainty in Measurement

preparing a fully documented, realistic uncertainty budget that is appropriate for the application

calculating a combined standard uncertainty using root-sum-of-squares, accounting for correlations where necessary

gathering information about uncertainty components from calibration reports or reference material report

calculating sensitivity coefficients either experimentally or by partial differentiation

calculating expanded uncertainty

using spreadsheets to calculate uncertainties

deciding if the uncertainty is suitable for the accuracy required for the test and establishing whether it is fit for purpose using the tolerance to uncertainty ratio (TUR)

using and interpreting mean, standard deviation, standard deviation of the mean, degrees of freedom, histograms and frequency plots, probability, normal probability plots and control charts

using the student's t-table to get a coverage factor for a particular level of confidence

using and interpreting significance tests, such as t-test, f-test and analysis of variance (ANOVA), variances, standard deviation of prediction and linear regression

using regression methods for calibration, linearity checks and comparing analytical methods

using and interpreting normal, rectangular, triangular distributions and the factors used to reduce each to a standard uncertainty

allocating degrees of freedom to each uncertainty component using the Welch-Satterthwaite equation

reporting results and uncertainties in the required formats.

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Knowledge Evidence

Must provide evidence that demonstrates knowledge of:

the steps in the measurement, test or calibration involved

the difference between errors, corrections and uncertainties

uncertainty in the uncertainty estimation process

uncertainty components that are common to the use of an instrument

uncertainty components that arise due to the instrument being used under different conditions to those when it was calibrated

uncertainty components, such as:

calibration uncertainty

instability or drift in the calibrated instrument

repeatability of the results

resolution or readability of the instrument

environmental influences, such as temperature, air pressure, humidity, vibration, electrical noise and gravity

reference material uncertainty

factors arising from using an instrument under a different operating environment or procedures (e.g. orientation of a transducer and immersion depth of a temperature probe)

reproducibility of quality control data

procedures for determining the uncertainty components associated with each of the inputs and whether they are significant and for applying appropriate corrections

manufacturer's specifications (e.g. instrument drift specification and reference materials)

procedures for determining uncertainty components from quality control data

the concept of degrees of freedom

the characteristics of a valid measurement

reporting requirements, such as the uncertainty in measurement (GUM), National Association of Testing Authorities (NATA) or other applicable reference material

confidence levels required by the National Measurement Act 1960 (e.g. 95% for most applications, but others may require a higher confidence level).

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