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Simultaneous Tests and Confidence Intervals for the Evaluation of Agricultural Field Trials
Author(s) -
Frömke Cornelia,
Bretz Frank
Publication year - 2004
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2004.1323
Subject(s) - macro , statistics , mathematics , multiplicity (mathematics) , factorial , block (permutation group theory) , computer science , algorithm , econometrics , combinatorics , mathematical analysis , programming language
Agricultural designs commonly involve the simultaneous analysis of more than two factors and more than two levels for each factor. This article addresses the use of adequate statistical tests while taking multiplicity into account. Two data sets and their appropriate statistical analysis are presented as illustrative examples. The first data set is a split‐plot design, with two fixed factors and a random block factor, and the second data set is a two‐factor factorial complete randomized design. Two SAS macros are presented to analyze the data sets properly in terms of the multiplicity problem, and these macros compute simultaneous confidence intervals and multiplicity‐adjusted p values. The two macros, called %SimultanTests and %SimultanIntervals , are based on exact evaluations of the underlying multivariate t distribution and are extensions of the published macros %SimTests and %SimIntervals . The macros are widely applicable tools, which can be used with relatively little effort for the analysis of many agricultural designs.