Paper · 2017 · Engenharia Agrícola

SPATIAL VARIABILITY OF SOYBEAN YIELD THROUGH A REPARAMETERIZED T-STUDENT MODEL

Rosangela C. Schemmer; Miguel A. Uribe-Opazo; Manuel Galea; et al.

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claims
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verbatim quotes
11
citations
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research areas
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Open access · cc-by

Abstract

The t-Student distribution has been used to the spatial dependence modelling of soybean yield as an alternative to the normal distribution, being used for data with heavier tails or discrepant values. However, a usual Student t-distribution does not allow direct comparisons of geostatistical methods with a normal distribution. The aim of this study was to assess the soybean yield spatial variability through a reparameterized t-Student linear model, comparing the results with those of a Gaussian linear model. For parameter estimation, a complete maximum likelihood (CML) method was used through an expectation-maximization (EM) algorithm. The maps constructed with both reparameterized t-Student and normal distributions are dissimilar and present a kappa index (K) equivalent to 0.64. The reparameterized t-Student distribution is an alternative in studying data with discrepant values, showing the ability to decrease the influence of these points.

Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗

The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.

Claims 2

Method / resourceobservedoriginal resultmeasured

Claim · model-written summary

The two model distributions produced dissimilar soybean yield maps with kappa 0.64.

Taxon
SOYBEANGlycine maxt0
Outcome
mapse0
Direction
dissimilare0
Value
0.64e0
Comparator
normal distributionse0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗

Verbatim

e0

“The maps constructed with both reparameterized t-Student and normal distributions are dissimilar and present a kappa index (K) equivalent to 0.64”

✓ located verbatim in the source · abstract, characters 644–789 · show in text ↑
t0

“SOYBEAN”

✓ located verbatim in the source · title, characters 23–30 · show in text ↑
Method / resourceauthor interpretationoriginal resultmeasured

Claim · model-written summary

The reparameterized t-Student distribution decreased the influence of discrepant values in soybean yield data.

Taxon
SOYBEANGlycine maxt0
Outcome
influence of these pointse0
Direction
decreasee0
Qualifier
data with discrepant valuese0

Not reportedComparatorValue

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗

Verbatim

e0

“The reparameterized t-Student distribution is an alternative in studying data with discrepant values, showing the ability to decrease the influence of these points.”

✓ located verbatim in the source · abstract, characters 791–955 · show in text ↑
t0

“SOYBEAN”

✓ located verbatim in the source · title, characters 23–30 · show in text ↑