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Some Investigations on Experimental Designs Incorporating Neighbour Effects

KrishiKosh

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Title Some Investigations on Experimental Designs Incorporating Neighbour Effects
Ph D
 
Creator ELDHO VARGHESE
 
Contributor Seema Jaggi
 
Subject crop residues, livestock, rice, biological phenomena, methane, inorganic compounds, fractionation, productivity, nitrogen, research methods
 
Description T-8394
In many agricultural field experiments, neighbour effects from adjacent units is a
serious source of bias in making comparison of treatment effects. The way to handle
such bias is to develop suitable statistical methodology and designs based on the
experimental situations. In response surface methodology, it is generally assumed that
the observations are independent and there is no effect of neighbouring units. But in
field experiments, the neighbour effects from the treatments applied to adjacent
neighbouring units may arise. The procedure for fitting a complete second order
response surface model incorporating equal neighbour effects from immediate left and
right neighbouring units has been derived. Conditions have been obtained for the
estimation of the coefficients of the model. First and second order response surface
model have also been studied under the assumption of differential neighbor effects
from both left and right units. A method of obtaining designs satisfying the derived
conditions has been developed. Blocking aspect in response surface designs in the
presence of neighbour effects has been studied and the conditions for orthogonal
estimation of parameters of first order model have been derived. Numerical examples
have been given for illustrating the experimental situation where experimental units
are grouped into complete/ incomplete blocks. There may arise situations where
neighbour effect is proportional to the direct effect of treatments. Information
matrices have been derived for one-sided and two-sided neighbour effects block
model under this set up. The existing neighbour balanced block designs have been
studied for different values of the proportionality parameter and their efficiencies
have been worked out. The situation where heterogeneity is present in the
experimental material in two directions, row-column designs are used. The
information matrices for estimating direct and neighbour effects of treatments under
different row-column model for directional and non-directional neighbour effects
have been derived. Methods of constructing these designs have been developed and
their characterization properties have also been studied. These designs are found to be
totally balanced/ variance balanced for estimating the direct and neighbour effects of
treatments.
 
Date 2016-11-01T10:07:03Z
2016-11-01T10:07:03Z
2011
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/83077
 
Format application/pdf
 
Publisher IARI, Some Investigations on Experimental Designs Incorporating Neighbour Effects