anosim(vegan)
anosim()所属R语言包：vegan
Analysis of Similarities
的相似性分析
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Analysis of similarities (ANOSIM) provides a way to test statistically whether there is a significant difference between two or more groups of sampling units.
分析的的相似之处（ANOSIM）提供一种方法来测试统计学采样单元的两个或两个以上的基团是否有显着差异。
用法----------Usage----------
anosim(dat, grouping, permutations = 999, distance = "bray", strata)
参数----------Arguments----------
参数：dat
Data matrix or data frame in which rows are samples and columns are response variable(s), or a dissimilarity object or a symmetric square matrix of dissimilarities.
矩阵数据的帧或数据框中的哪些行样品和列是响应变量（s），或相异对象或对称方阵异同。
参数：grouping
Factor for grouping observations.
分组观察因素。
参数：permutations
Number of permutation to assess the significance of the ANOSIM statistic.
编号的置换，以评估的ANOSIM统计意义。
参数：distance
Choice of distance metric that measures the dissimilarity between two observations . See vegdist for options. This will be used if dat was not a dissimilarity structure or a symmetric square matrix.
选择距离度量，测量两次观测之间的相异。见vegdist的选项。这将用于如果dat不是相异结构或对称的正方形矩阵。
参数：strata
An integer vector or factor specifying the strata for permutation. If supplied, observations are permuted only within the specified strata.
一个整数向量或因素确定地层的置换。如果提供，观测置换仅在指定的阶层。
Details
详细信息----------Details----------
Analysis of similarities (ANOSIM) provides a way to test statistically whether there is a significant difference between two or more groups of sampling units. Function anosim operates directly on a dissimilarity matrix. A suitable dissimilarity matrix is produced by functions dist or vegdist. The method is philosophically allied with NMDS ordination (monoMDS), in that it uses only the rank order of dissimilarity values.
分析的的相似之处（ANOSIM）提供一种方法来测试统计学采样单元的两个或两个以上的基团是否有显着差异。功能anosim直接经营上的相异度矩阵。合适的相异度矩阵是由功能dist或vegdist。该方法在哲学上结盟与NMDS协调（monoMDS），因为它使用的相异值的排名顺序。
If two groups of sampling units are really different in their species composition, then compositional dissimilarities between the groups ought to be greater than those within the groups. The anosim statistic R is based on the difference of mean ranks between groups (r_B) and within groups (r_W):
如果两个群体的取样单位是真的不同，它们的物种的组合物，那么基团的成分异同应该是大于组内。 anosim统计R是根据不同群体之间的平均等级（r_B）和组内（r_W）：
The divisor is chosen so that R will be in the interval -1 … +1, value 0 indicating completely random grouping.
选择除数是R将在区间-1 … +1值0的，表示完全随机分组。
The statistical significance of observed R is assessed by permuting the grouping vector to obtain the empirical distribution of R under null-model. See permutations for additional details on permutation tests in Vegan.
的统计显着观察到的R被评估通过置换分组矢量空模型下，得到的经验分布R。见permutations排列测试，素食主义者的更多细节。
The function has summary and plot methods. These both show valuable information to assess the validity of the method: The function assumes that all ranked dissimilarities within groups have about equal median and range. The plot method uses boxplot with options notch=TRUE and varwidth=TRUE.
该功能有summary和plot方法。这些都显示出有价值的信息，以评估该方法的有效性：该函数假设所有组内的排名相异约等于中位数和范围。 plot方法使用boxplot选项notch=TRUE和varwidth=TRUE。
值----------Value----------
The function returns a list of class "anosim" with following items:
该函数返回一个列表类"anosim"的下列项目：
参数：call
Function call.
函数调用。
参数：statistic
The value of ANOSIM statistic R
的价值的ANOSIM统计R，
参数：signif
Significance from permutation.
从排列的意义。
参数：perm
Permutation values of R
置换值R
参数：class.vec
Factor with value Between for dissimilarities between classes and class name for corresponding dissimilarity within class.
价值因子与Between相应的相异类内类和类的名称的异同。
参数：dis.rank
Rank of dissimilarity entry.
排名相异进入。
参数：dissimilarity
The name of the dissimilarity index: the "method" entry of the dist object.
的相异指数："method"进入dist对象的名称。
注意----------Note----------
The anosim function can confound the differences between groups and dispersion within groups and the results can be difficult to interpret (cf. Warton et al. 2012). The function returns a lot of information to ease studying its performance. Most anosim models could be analysed with adonis which seems to be a more robust alternative.
anosim功能可以混淆之间的差异，组和组内的分散，其结果可能是难以解释的（见沃顿等人，2012）。该函数返回大量的信息，以减轻学习它的性能。大多数anosim模型进行分析，adonis这似乎是一个更强大的替代。
（作者）----------Author(s)----------
Jari Oksanen, with a help from Peter R. Minchin.
参考文献----------References----------
in community structure. Australian Journal of Ecology 18, 117–143.
analyses confound location and dispersion effects. Methods in Ecology and Evolution, 3, 89–101
参见----------See Also----------
mrpp for a similar function using original dissimilarities instead of their ranks. dist and vegdist for obtaining dissimilarities, and rank for ranking real values. For comparing dissimilarities against continuous variables, see mantel. Function adonis is a more robust
mrpp类似的功能，采用独创的不同点，而不是他们的行列。 dist和vegdist为获得不同点，和rank用于实际值排名。对连续变量的比较异同，mantel。功能adonis是一个更强大
实例----------Examples----------
data(dune)
data(dune.env)
dune.dist <- vegdist(dune)
attach(dune.env)
dune.ano <- anosim(dune.dist, Management)
summary(dune.ano)
plot(dune.ano)
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注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
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发表于 2012-10-1 15:02:40
