shift.com(smatr)
shift.com()所属R语言包：smatr
Test for no mean shift along a common (standardised) major axis
没有沿着一个共同的（标准）长轴均值漂移测试
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Test if several groups of observations have no shift in location along major axis or standardised major axis lines with a common slope. This can now be done via sma(y~x+groups, type="shift"), see help on the sma function.
测试几组观察有没有转变位置沿长轴或标准化的主要轴线与一个共同的斜率。现在可以通过sma(y~x+groups, type="shift")信息，请参阅上的sma功能的帮助。
用法----------Usage----------
intercept = TRUE, V=array( 0, c( 2,2,length(unique(groups)))),
参数----------Arguments----------
参数：y
The Y-variable for all observations (as a vector)
Y-的所有观测的变量（作为一个向量）
参数：x
The X-variable for all observations (as a vector)
X-变量的所有观测值（作为一个向量）
参数：groups
Coding variable identifying which group each observation belongs to (as a factor or vector)
编码变量确定每个观测值属于哪个组（作为一个因素或矢量）
参数：data
(optional) data frame containing the data
（可选的）数据框包含的数据
参数：method
The line fitting method:
该生产线拟合的方法：
'SMA' or 1standardised major axis (this is the default)
“SMA”或1standardised长轴（这是默认设置）
'MA' or 2major axis
MA或2major轴的
参数：intercept
(logical) Whether or not the line includes an intercept.
（逻辑）是否该系列包括拦截。
FALSE no intercept, so the line is forced through the origin
FALSE没有拦截，因此被强制通过原点
TRUE an intercept is fitted (this is the default)
TRUE拦截安装（这是默认的）
参数：V
The estimated variance matrices of measurement error, for each group. This is a 3-dimensional array with measurement error in Y in the first row and column, error in X in the second row and column, and groups running along the third dimension. Default is that there is no measurement error.
测量误差的估计方差矩阵，每个组。与Y中的测量误差的第一行和列中，X中的第二行和列中的错误，并沿第三维度上运行的组中，这是一个3维阵列。默认是不存在测量误差。
参数：group.names
(optional: rarely required). A vector containing the labels for "groups". (Only actually useful for reducing computation time in simulation work).
（可选：很少需要）。一个向量“组”的标签。 （实际上只用在模拟工作，减少计算时间）。
Details
详细信息----------Details----------
Calculates a Wald statistic to test for no shift along several MA's or SMA's of common slope. This is done by testing for equal fitted axis means across groups.
计算一个Wald统计量检验为无移位沿着几个MA或SMA的共同的斜率。这是通过平等装轴装置，各组的测试。
Note that this test is only valid if it is reasonable to assume that the axes for the different groups all have the same slope.
注意，这个测试是有效的，如果它是合理的假设，为不同的组所有轴具有相同的斜率。
The test assumes the following:
测试假设如下：
each group of observations was independently sampled
观察各组的独立采样
the axes fitted to all groups have a common slope
轴安装到所有群体都有一个共同的斜率
y and x are linearly related within each group
y和x是线性相关的每个组内的
fitted axis scores independently follow a normal distribution with equal variance at all points along the line, within each group
独立装轴的分数遵循沿线的所有点等于方差的正态分布，各组内
Note that we do not need to assume equal variance across groups, unlike in tests comparing several linear regression lines.
请注意，我们并不需要承担平等的差异，各组不同，在测试中，比较了几种线性回归线。
The assumptions can be visually checked by plotting residuals against fitted axis scores, and by constructing a Q-Q plot of residuals against a normal distribution, available using
假设可以直观地检查绘制残差，对装轴的分数，并通过建设的残留物对正常的分布，使用的QQ图
plot.sma(sma.object,which="residual").
plot.sma(sma.object,which="residual")。
On a residual plot, if there is a distinct increasing or decreasing trend within any of the groups, this suggests that all groups do not share a common slope.
剩余的图，如果有一个明显的增加或减少的趋势在任何一组，这表明，所有群体都有一个共同的斜率。
A plot of residual scores against fitted axis scores can also be used as a visual test for no shift. If fitted axis scores systematically differ across groups then this is evidence of a shift along the common axis.
一个图的剩余分数对装轴的分数也可以被用来作为一个可视化的测试，无移位。如果安装轴评分系统的不同而不同群体的话，这就是证据沿共同轴线的转变。
The common slope (b) is estimated from a maximum of 100 iterations, convergence is reached when the change in b is < 10^-6.
共同的斜率（b），估计从最高的100次迭代，达到收敛时，b改变< 10^-6。
值----------Value----------
参数：stat
The Wald statistic testing for no shift along the common axis
Wald统计量的共同轴线沿线无移位测试
参数：p
The P-value of the test. This is calculated assuming that stat has a chi-square distribution with (g-1) df, if there are g groups
P-值的测试。这是计算假设统计，卡方分布（G-1），DF，如果有G功能组
参数：f.mean
The fitted axis means for each group
装轴是指每个组
（作者）----------Author(s)----------
Warton, D. <a href="mailto avid.Warton@unsw.edu.au">David.Warton@unsw.edu.au</a>, translated to R by Ormerod, J. 2005-12-08
参考文献----------References----------
<h3>See Also</h3>
实例----------Examples----------
#load leaf longevity data[加载叶寿命数据]
data(leaflife)
#Test for common SMA slope amongst species at low rainfall sites[种在低雨量站点之间的共同SMA斜率测试]
#with different levels of soil nutrients[不同程度的土壤养分]
leaf.low.rain=leaflife[leaflife$rain=='low',]
slope.com(log10(longev), log10(lma), soilp, data=leaf.low.rain)
#Now test for no shift along the axes of common slope, for sites[沿轴共同的斜率无移位，现在测试的网站]
#with different soil nutrient levels but low rainfall:[不同土壤养分的水平，但低降雨量：]
shift.com(log10(longev), log10(lma), soilp, data = leaf.low.rain)
#Now test for no shift along the axes of common slope, for sites[沿轴共同的斜率无移位，现在测试的网站]
#with different soil nutrient levels but low rainfall:[不同土壤养分的水平，但低降雨量：]
shift.com(log10(longev), log10(lma), soilp, data = leaf.low.rain,
method='MA')
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
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。
注2：由于是机器人自动翻译，难免有不准确之处，使用时仔细对照中、英文内容进行反复理解，可以帮助R语言的学习。
注3：如遇到不准确之处，请在本贴的后面进行回帖，我们会逐渐进行修订。
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发表于 2012-9-30 10:15:12
