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Determination of leaf area by rating in comparison with geometric shapes
Author(s) -
HUMPHRIES E. C.,
FRENCH S. A. W.
Publication year - 1964
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1964.tb01191.x
Subject(s) - series (stratigraphy) , geometric standard deviation , geometric mean , geometric series , mathematics , ellipse , standard deviation , statistics , geometric progression , least squares function approximation , geometry , arithmetic , biology , mathematical analysis , estimator , paleontology , power series
SUMMARY The accuracy of the rating method of determining leaf area has been further studied using geometric shapes, viz. circles, squares and ellipses in preference to facsimile leaf shapes. The standards were arranged in geometric or arithmetic series. Ellipses gave a worse estimate of area than squares or circles. Shapes arranged in a geometric series underestimated true area, whereas those in arithmetic series overestimated it. The geometric series had a smaller deviation. For practical purposes it does not matter which series is used. The earlier preference for a geometric series, based on theoretical considerations, seems unjustified. The mean leaf area of six sugar beet or potato plants was estimated with a deviation of 3% or less using circles or squares as standards. Even when each leaf is estimated as accurately as possible, a deviation in estimating total area obtained can exceed 1%. Results from ratings in arithmetic series are more easily converted to actual areas than those in geometric series.