Construction and optimality of affine-resolvable designs
Construction and optimality of affine-resolvable designs
复制标题
仿射解析设计的构造和优化
DOI:
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发表时间:
1995
期刊:
影响因子:
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通讯作者:
H. Monod
中科院分区:
文献类型:
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作者:
R. A. Bailey;H. Monod
SUMMARY Affine-resolvable designs are constructed from orthogonal arrays and shown to be optimal among resolvable designs with respect to the usual criteria. Tables and text show how to construct such designs in up to seven replicates whenever the number of treatments properly divides the square of the block size. Data from experiments which use affine- resolvable designs can be simply analysed by using pseudofactors. In many experiments where an incomplete-block design is used, a resolvable design, that is, a design in which the blocks can be partitioned into sets containing each treatment once, is desirable. Sometimes the blocks are naturally grouped into larger blocks contain- ing each treatment exactly once. An example from microbiology is an experiment in which jars of treated bacteria are placed in incubators so that the bacteria may multiply; blocks are the shelves within the incubators and large blocks are the incubators. Use of a resolv- able design ensures that the large blocks are orthogonal to treatments. In other cases, particularly in agricultural trials, neighbouring blocks are grouped into large blocks for management purposes. Then a resolvable design not only keeps management effects ortho- gonal to treatments, it also gives some protection against the loss of a whole large block, for all treatments are disadvantaged equally by such a loss. The large blocks are often called replicates, although somewhat ambiguously, because their existence is independent of the treatment allocation. Suppose that a resolvable design is needed for v treatments in blocks of size k, where v = sk for some integer s greater than 1, and that r replicates are required. For r = 2, Williams, Patterson & John (1976) showed that an optimal resolvable design is equivalent to an optimal incomplete-block design for s treatments in s blocks of size k. Thus optimality results about nonresolvable designs may be used to find the most efficient resolvable