Published: Jan 1952
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Equations relating the fundamental sampling constants of a coal (as variances) to the observed variance of a series of samples composed of N increments each of weight w are given. Suggestions are made for estimating the “trend” variance and charts are given for the more precise determination of the expected unit increment variance and the variance of the process of reduction and analysis of the gross sample. Several numerical examples are given to show the effect of changing the increment weight on the number required and to show the effect of changing the specified number on the total sample weight.
Bertholf, W. M.
Efficiency Engineer By-Product Coke Plant, Colorado Fuel and Iron Corp., Pueblo, Colo