Testing the significance of canonical axes in redundancy analysis
Testing the significance of canonical axes in redundancy analysis
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DOI：
10.1111/j.2041-210x.2010.00078.x
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发表时间：
2011-06-01
影响因子：
6.6
通讯作者：
ter Braak, Cajo J. F.
中科院分区：
文献类型：
--
作者：
Legendre, Pierre;Oksanen, Jari;ter Braak, Cajo J. F.
P>1。在冗余分析中，单个典型轴的显著性检验允许研究人员确定哪些轴代表可以与随机区分开的变异。沿显著轴的变化沿着可以被映射，用于绘制双标图或通过随后的分析解释，而不显著的轴可以从进一步的解释中删除。三种方法已实施的计算机程序来测试的典范轴的意义，他们在本文中进行了比较。所有单个典型轴的同时检验，由于其简单性而吸引人，对于与数据中真实关系对应的轴，产生了不正确的（高度膨胀的）I型错误水平，因此它是无效的。在“vegan”R软件包中实现的“边际”测试方法和在CANOCO程序中实现的“向前”测试方法被发现具有正确的I型错误水平和可比的功效。残差的排列比原始数据的排列获得更大的功效。在本文的补充中发现的R函数提供了第一个正式描述的'边际'和'向前'测试方法。
P>1. Tests of significance of the individual canonical axes in redundancy analysis allow researchers to determine which of the axes represent variation that can be distinguished from random. Variation along the significant axes can be mapped, used to draw biplots or interpreted through subsequent analyses, whilst the nonsignificant axes may be dropped from further consideration.2. Three methods have been implemented in computer programs to test the significance of the canonical axes; they are compared in this paper. The simultaneous test of all individual canonical axes, which is appealing because of its simplicity, produced incorrect (highly inflated) levels of type I error for the axes following those corresponding to true relationships in the data, so it is invalid. The 'marginal' testing method implemented in the 'vegan' R package and the 'forward' testing method implemented in the program CANOCO were found to have correct levels of type I error and comparable power. Permutation of the residuals achieved greater power than permutation of the raw data.3. R functions found in a Supplement to this paper provide the first formal description of the 'marginal' and 'forward' testing methods.