Pavement
Estimating Uncertainty in Measurements Made on Materials
- Publication no: AP-T79-08
- ISBN: 978-1-921329-53-1
- Published: 16 May 2008
- PDF (free) Download
This document provides some guidelines on the estimation of measurement uncertainty and sampling variation. The procedures are demonstrated through a worked example based on a soil moisture content test. Estimation of the standard deviation for each source of uncertainty and the sensitivity of the source of uncertainty are discussed extensively. Additional examples are used to illustrate some of the concepts. In addition to working through the example, some ideas are proposed on how readers may obtain estimates of sensitivities to variables that do not directly impact on the calculation of the measurand. Three appendices are included covering, methods of calculating the total uncertainty, analysis of inter-laboratory trials and sampling variance when estimating a lot average.
- AP-T79/08 Estimating Uncertainty in Measurements Made on Materials
- 1. INTRODUCTION
- 1.1. How the Guide is Structured
- 1.2. Emphasis on Sampling Variation
- 2. AN EXAMPLE: MOISTURE CONTENT OF SOIL
- 2.1. Introduction
- 2.2. Step 1: Identifying Components of Uncertainty
- 2.3. Step 2: Estimating Standard Deviations
- 2.4. Step 3: Estimating Sensitivities
- 2.5. Step 4: Estimating Total Uncertainty
- 3. TERMINOLOGY
- 3.1. Measurand
- 3.2. Mean, Variance and Standard Deviation
- 3.3. Uncertainty and Variation
- 3.4. Random and Systematic Effects
- 3.5. Closing Comment about Terminology
- 4. IDENTIFYING COMPONENTS OF UNCERTAINTY
- 4.1. First Approach: List all Components of Uncertainty Separately
- 4.2. Second Approach: Distinguish Components which will be Separated Experimentally
- 4.3. Comparison between these Two Approaches
- 5. ESTIMATING VARIANCE COMPONENTS
- 6. ESTIMATING SENSITIVITIES
- 6.1. Sensitivity to Temperature for Particle Loss Method
- 6.2. Sensitivity of the Particle Loss Method to the Number of Revolutions
- 6.3. Sensitivity of the Particle Loss Method to the Internal Diameter of the Drum
- 7. ESTIMATING TOTAL UNCERTAINTY CONSIDERING ALL THE COMPONENTS
- 7.1. The Law of Propagation of Uncertainty
- 8. DISCUSSION
- REFERENCES
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