有时,如果我们有一个分类变量,其值为Yes/No或Male/Female等。简单回归分析为分类变量的每个值提供多个结果。 在这种情况下,我们可以通过将分类变量与预测变量一起使用并比较分类变量的每个级别的回归线来研究分类变量的影响。 这种分析被称为Analysis of Covariance也称为ANCOVA。 例子(Example) 考虑R内置的数据集mtca...
除参数“data”外,所有其他参数均为可选参数。 例子(Example) 从2012年1月开始考虑一个地方的年降雨量详细信息。我们创建一个R时间序列对象,为期12个月并绘制它。 # Get the data points in form of a R vector. rainfall <- c(799,1174.8,865.1,1334.6,635.4,918.5,685.5,998.6,784.2,985,882.8,1...
Summary This chapter describes how to use analysis of covariance (ANCOVA) in a scenario where an interval (measured) endpoint may be affected by two factors, one of which is also interval, but the other nominal. It shows an example of a clinical trial where ANCOVA would be appropriate. The...
Themultcomparefunction can test either slopes, intercepts, or population marginal means (the predicted MPG of the mean weight for each group). The example inAnalysis of Covariance Toolshows that the slopes are not all the same, but could it be that two are the same and only the other one ...
Analysis of Covariance A one-wayanalysis of covariance(ANCOVA) allows one to model group effects, that is, the mean of each ofQgroups. This model includes the one-sample and two-samplet-tests, that is, the cases when 1≤Q≤2. In our example, let the number of groups beQ=3, where ...
Analysis_of_Covariance AnalysisofCovariance:ANCOVA JackyCheng12/20,2006 共變數分析是一種統計控制的方法。它是利用直線迴歸法將其他影響依變數的因素，從變數中剔除，然後根據調整過後的分數，進行變異數分析，因此，共變數分析可說是變異數分析與直線迴歸的合併使用（張紹勳、張紹評、林秀娟，民83）。共變數分析的...
Use analysis of covariance (ancova) when you want to compare two or more regression lines to each other; ancova will tell you whether the regression lines are different from each other in either slope or intercept.When to use itUse analysis of covariance (ancova) when you have two ...
In this chapter, we will first give a simple example. We will then describe the model for analysis of covariance, the problems of interpretation, and the assumptions that must be made. Next, we will discuss the advantages and disadvantages of analysis of covariance, as compared with other ...
(redirected from Analysis of covariance)Also found in: Thesaurus, Medical, Financial, Acronyms, Encyclopedia, Wikipedia. a·nal·y·sis (ə-năl′ĭ-sĭs) n. pl. a·nal·y·ses (-sēz′) 1. a. The separation of an intellectual or material whole into its constituent parts for...
Example 3.2Covariance analysis of numeric attributes Consider Table 3.2, which presents a simplified example of stock prices observed at five time points for AllElectronics and HighTech, a high-tech company. If the stocks are affected by the same industry trends, will their prices rise or fall to...