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SOUTH AFRICAN QUALIFICATIONS AUTHORITY 
REGISTERED UNIT STANDARD: 

Apply the ISO document "guide to the expression of uncertainty in measurement" to estimate uncertainty of measurement 
SAQA US ID UNIT STANDARD TITLE
119255  Apply the ISO document "guide to the expression of uncertainty in measurement" to estimate uncertainty of measurement 
ORIGINATOR
SGB Engineering 
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-  
FIELD SUBFIELD
Field 06 - Manufacturing, Engineering and Technology Engineering and Related Design 
ABET BAND UNIT STANDARD TYPE PRE-2009 NQF LEVEL NQF LEVEL CREDITS
Undefined  Regular  Level 5  Level TBA: Pre-2009 was L5 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Reregistered  2018-07-01  2023-06-30  SAQA 06120/18 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2024-06-30   2027-06-30  

In all of the tables in this document, both the pre-2009 NQF Level and the NQF Level is shown. In the text (purpose statements, qualification rules, etc), any references to NQF Levels are to the pre-2009 levels unless specifically stated otherwise.  

This unit standard does not replace any other unit standard and is not replaced by any other unit standard. 

PURPOSE OF THE UNIT STANDARD 
This unit standard will be useful for people who use, test and calibrate measuring artifacts and equipment. Persons credited with this unit standard are able to demonstrate fundamental understanding and application of concepts of accuracy, precision, uncertainty, errors and basic contributors of uncertainty of measurement, to measurement and the estimation of uncertainty of measurement, using statistical principles.

Persons credited with this unit standard are able to:
  • Define and explain the concepts and methodology of uncertainty of measurement.
  • Analyse the basic contributors to uncertainty of measurement.
  • Estimate the uncertainty of measurement.
  • Evaluate and record the estimate of uncertainty of measurement. 

  • LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
    Competence in the following:
  • Mathematics - level 5.
  • Measurement Statistics - level 4
  • Define the role, functions and operation of the international measurement system 

  • UNIT STANDARD RANGE 
    The scope of this unit standard is limited to the ISO document "Guide to the estimation of uncertainty of measurement". 

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    Define and explain the concepts and methodology of uncertainty of measurement. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The methodology of the ISO guide is explained in terms of international best practice. 

    ASSESSMENT CRITERION 2 
    The definition of accuracy, precision, errors and uncertainties are explained in terms of the relationship of these concepts to each other. 

    ASSESSMENT CRITERION 3 
    The identification of the basic contributors to uncertainty of measurement is explained with reference to the above measurement concepts. 

    SPECIFIC OUTCOME 2 
    Analyse the basic contributors to uncertainty of measurement. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    A mathematical model is formulated in terms of the measurement system. 

    ASSESSMENT CRITERION 2 
    An Uncertainty Matrix is produced in terms of the basic contributors to measurement uncertainty. 

    ASSESSMENT CRITERION 3 
    The contributors are evaluated in terms of Type A or B method of analysis. 

    SPECIFIC OUTCOME 3 
    Estimate the uncertainty of measurement. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    Distribution types and divisors are identified in terms of Type A or B method of analysis. 

    ASSESSMENT CRITERION 2 
    Sensitivity coefficients are computed in terms of measurement units. 

    SPECIFIC OUTCOME 4 
    Evaluate and record the estimate of uncertainty of measurement. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The uncertainty of measurement is evaluated and recorded according to the application and the associated Best Measurement Capability(BMC). 


    UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS 
    Anyone assessing a learner against this unit standard must be a registered SANAS Technical Assessor and registered as an assessor with the relevant ETQA.

    Any institution offering learning that will enable achievement of this unit standard must be accredited as a provider through the relevant ETQA by SAQA.

    Moderation of assessment will be overseen by the relevant ETQA according to the moderation guidelines and the agreed ETQA procedures. 

    UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
    Essential embedded knowledge will be assessed through assessment of the specific outcomes in terms of the stipulated assessment criteria. Candidates are unlikely to achieve all the specific outcomes, to the standards described in the assessment criteria, without knowledge of the listed embedded knowledge. This means that for the most part, the possession or lack of the knowledge can be directly inferred from the quality of the candidate's performance. Where direct assessment of knowledge is required, assessment criteria have been included in the body of the unit standard.

    The following embedded knowledge is addressed in an integrated way in the unit standard:

    2.1. Introduction to Uncertainty of Measurement.
    Why uncertainty of measurement? A uniform approach: introduction to the ISO Guide. Basic methodology. Model the measurement system. Identify the sources of error. Categorize as type A or type B. Manipulate appropriately. Combine to obtain a combined standard uncertainty. Expand to obtain an expanded uncertainty at an appropriate confidence level.

    2.2. Definitions.
    True Value, Conventional true value, Measurement, Measure and Measurement result, Influence quantity, Uncorrected result, Corrected result, Accuracy of measurement, Repeatability, Reproducibility, Uncertainty, Error, Random error, Systematic error, Correction, Confidence interval, Confidence level, Uncertainty Contributors, Type A and Type B, Compliance with specifications.

    2.3. Sources of Uncertainty.
    Standards and references, Unit under test, Instruments, Method/Procedure, Environment, Personnel, Other.

    2.4. Basic Statistics.
    Reason for Statistical Approach, What is Statistics, Basic Terms, Histograms, Mean, Median, Mode, Variance, Standard Deviation, Frequency based approaches, Frequency Distributions (Normal, Rectangular, Triangular, U-shaped)
    Central Limit Theorem, Populations/Samples, Probability, Estimates of Statistics, Experimental Standard Deviation, Experimental Variance, Degrees of freedom, Experimental Standard Deviation of the Mean, Student's "t" distributions, Fitted curves, Estimate Uncertainty of Measurement in drift, Sensitivity coefficients, Conversion between confidence levels.

    2.5. Applying the ISO Guide.
    Flow chart, Evaluating the standard uncertainties, Determining the combined standard uncertainty, Determining the expanded uncertainty.

    2.6. Mathematically modelling the measurement.

    2.7. Other principles.
    Correlation, Higher order terms.

    2.8. Reporting of uncertainty.
    Certificates, Statements of compliance. 

    UNIT STANDARD DEVELOPMENTAL OUTCOME 
    N/A 

    UNIT STANDARD LINKAGES 
    N/A 


    Critical Cross-field Outcomes (CCFO): 

    UNIT STANDARD CCFO IDENTIFYING 
    Identify and solve problems and make decisions using critical and creative thinking.
    Note: The ability of the candidate to identify contributors, estimate and evaluate uncertainty of measurement - specific outcome 2, 3 and 4. 

    UNIT STANDARD CCFO WORKING 
    Work effectively with others as members of a team, group, organisation or community.
    Note: This is not addressed in any of these specific outcomes. 

    UNIT STANDARD CCFO ORGANISING 
    Organise and manage themselves and their activities responsibly and effectively.
    Note: This is not addressed in any of these specific outcomes. 

    UNIT STANDARD CCFO COLLECTING 
    Collect, analyse, organise and critically evaluate information.
    Note: The ability of the candidate to identify contributors, estimate and evaluate uncertainty of measurement. - specific outcome 2, 3 and 4. 

    UNIT STANDARD CCFO COMMUNICATING 
    Communicate effectively, using visual, mathematical and / or language skills in the modes of oral and / or written presentations.
    Note: The appropriate communication with customers, laboratory manager and personnel with regard to estimation of uncertainty of measurement related to the measurement results, will indicate his/her proficiency in effective communication. 

    UNIT STANDARD CCFO SCIENCE 
    Use science and technology effectively and critically showing responsibility towards the environment and health of others.
    Note: This is not addressed in any of these specific outcomes. 

    UNIT STANDARD CCFO DEMONSTRATING 
    Demonstrate an understanding of the world as a set of related systems by recognising that problem-solving contexts do not exist in isolation.
    Note: This is not addressed in any of these specific outcomes. 

    UNIT STANDARD ASSESSOR CRITERIA 
    N/A 

    REREGISTRATION HISTORY 
    As per the SAQA Board decision/s at that time, this unit standard was Reregistered in 2012; 2015. 

    UNIT STANDARD NOTES 
    Notes to assessors

    Assessors should keep the following principles in mind when designing and conducting assessments against this unit standard:
  • Focus the assessment activities on gathering evidence in terms of the main outcome expressed in the title to ensure assessment is integrated rather than fragmented. Remember we want to declare the person competent in terms of the title. Where assessment at title level is unmanageable, then focus assessment around each specific outcome, or groups of specific outcomes.
  • Make sure evidence is gathered across the entire range, wherever it applies. Assessment activities should be as close to the real performance as possible, and where simulations or role-plays are used, there should be supporting evidence to show the candidate is able to perform in the real situation.
  • Do not focus the assessment activities on each assessment criterion. Rather make sure the assessment activities focus on outcomes and are sufficient to enable evidence to be gathered around all the assessment criteria.
  • The assessment criteria provide the specifications against which assessment judgements should be made. In most cases, knowledge can be inferred from the quality of the performances, but in other cases, knowledge and understanding will have to be tested through questioning techniques. Where this is required, there will be assessment criteria to specify the standard required.
  • The task of the assessor is to gather sufficient evidence, of the prescribed type and quality, as specified in this unit standard, that the candidate can achieve the outcomes again and again and again. This means assessors will have to judge how many repeat performances are required before they believe the performance is reproducible.
  • All assessments should be conducted in line with the following well documented principles of assessment: appropriateness, fairness, manageability, integration into work or learning, validity, direct, authentic, sufficient, systematic, open and consistent

    The following particular issues should be taken into consideration when assessing against this unit standard:

    Unit standard justification

    1. Level.

    Attribute-Level
    Applied Competence-5
    Autonomy of Learning-5

    Actual Level Assigned: 5

    2. Credits.

    Total hours required by the learner to achieve the required outcome:

    Activity-Hours
    Classroom Teaching-24
    On-The-Job Training-26
    Mentoring required--
    Other (Specify)--
    Total-50

    Credits Assigned: 5 

  • QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Core  57228   National Certificate: Metrology  Level 5  Level TBA: Pre-2009 was L5  Reregistered  2023-06-30  EWSETA 
    Elective  49746   National Certificate: Measurement, Control and Instrumentation  Level 5  Level TBA: Pre-2009 was L5  Reregistered  2023-06-30  EWSETA 


    PROVIDERS CURRENTLY ACCREDITED TO OFFER THIS UNIT STANDARD: 
    This information shows the current accreditations (i.e. those not past their accreditation end dates), and is the most complete record available to SAQA as of today. Some Primary or Delegated Quality Assurance Functionaries have a lag in their recording systems for provider accreditation, in turn leading to a lag in notifying SAQA of all the providers that they have accredited to offer qualifications and unit standards, as well as any extensions to accreditation end dates. The relevant Primary or Delegated Quality Assurance Functionary should be notified if a record appears to be missing from here.
     
    1. NATIONAL METROLOGY INSTITUTE OF SOUTH AFRICA 



    All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.