Variability Associated with Determining Grade Factors and Support Price of Farmers Stock Peanuts¹

Authors: , ,


Replicated grade samples were taken from runner, Spanish, and virginia-type farmers stock peanut lots. Each sample was graded according to the procedures of the Federal State Inspection Service. The variability of %foreign material (%FM) and %loose shelled kernels (%LSK) associated with a 1800-g sample was measured. The variability of %sound mature kernels (%SMK), %sound splits (SS), %other kernels (%OK), %damage (%DAM), and %extra large kernels (%ELK) associated with a 500-g sample was also measured. The variance was shown to be a function of the magnitude of the grade determination and was described by a relationship derived from binomial theory. From the measured grade factors, the support price per gross ton was calculated for each grade sample using the 1988 USDA loan schedule. The variance of the price per gross ton was also estimated and appeared to be independent of the price per gross ton. The coefficients of variation averaged across all lots tested were 21.1, 18.7, 2.6, 21.2, 14.0, 55.3, 7.8, and 2.4% for %FM, %LSK, %SMK, %SS, %OK, %DAM, %ELK, and price per gross ton, respectively. The computed price per gross ton of a farmers lot that has a true value of $600 was estimated to vary from $573 to $627 95% of the time when using the 500 and 1800 g grade sample to measure each grade factor.

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Keywords: peanuts, grading, errors, variability

How to Cite: Whitaker, T. , Dickens, J. & Giesbrecht, F. (1991) “Variability Associated with Determining Grade Factors and Support Price of Farmers Stock Peanuts¹”, Peanut Science. 18(2). doi:

Author Notes

1Paper No. 9003 of the Journal Series of the Department of Biological and Agricultural Engineering, N. C. State University, Raleigh, N.C., 276957625. The use of trade names in this publication does not imply endorsement by the United States Department of Agriculture or the North Carolina Agricultural Research Service of the product named nor criticism of similar ones not mentioned.