R语言中ancova协方差分析数据怎么导入？

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R语言中ancova协方差分析数据怎么导入？,第1张

ancova()提供了协方差分析计算,调用方式是：

ancova(formula,data.in=sys.parent(),x,groups)

实例：为研究ABC三种饲料对猪的催肥效果,每种饲料养8头猪一段时间,测得每头猪的初始重量（X）和增重（Y）,分析三种饲料对猪的催肥效果是否相同?

>#建立数据集

>feed Weight_Initial Weight_Increment data_feed anova(lm(Weight_Increment~Weight_Initial+feed),data=data_feed)

Analysis of Variance Table

Response:Weight_Increment

Df Sum Sq Mean Sq F value Pr(>F)

Weight_Initial 1 1621.12 1621.12 142.445 1.496e-10 ***

feed 2 707.22 353.61 31.071 7.322e-07 ***

Residuals 20 227.61 11.38

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Signif.codes:0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

>anova(lm(Weight_Increment~Weight_Initial*feed),data=data_feed)

Analysis of Variance Table

Response:Weight_Increment

Df Sum Sq Mean Sq F value Pr(>F)

Weight_Initial 1 1621.12 1621.12 162.4949 1.897e-10 ***

feed 2 707.22 353.61 35.4443 5.726e-07 ***

Weight_Initial:feed 2 48.04 24.02 2.4076 0.1184

Residuals 18 179.58 9.98

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Signif.codes:0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1