Automated Test Procedures

ASTM D6518 Coal Bias Testing

Bias testing of mechanical coal sampling systems is critical for ensuring that coal properties are accurately measured. Many companies often struggle with processing bias test data as specified by ASTM D6518.

DataWolff automates all three tests specified in this standard that include: the Student-t test; Hotelling’s T Squared test; and the Wilcoxon Signed Rank Non Parametric test. The automated data analyses create workbooks that indicate whether the system passed or failed, or whether the results were inconclusive. In addition time series of all data are automatically created. The plots below present ellipses for a Hotelling’s T Squared test that provide a clear interpretation of a test. Download the workbooks referenced by the links below to review example results from the ASTM D6518 analysis scripts.

Example Plots Created by the Hotelling’s T Squared Analysis

Click the image for a larger view

Graph displaying test elipse

Test Ellipse Lies Within Ellipse Defined by Largest Tolerable Bias Values – No bias Detected in Measurement System

 
Graph displaying test elipse

Test Ellipse Touches Ellipse Defined by Largest Tolerable Bias Values – Bias Test Is Inconclusive

 
Graph displaying test elipse

Test Ellipse Lies Outside of Ellipse Defined by Largest Tolerable Bias Values – System Appears to Be Biased

 

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