随机区组设计又叫完全随机区组设计,通过使用区组的方法较少误差变异,通过区组方法分离出由无关变量引起的变异,使其不出现在处理效应和误差的变异中。
例如:水稻参试品种有A-F五种,重复4次,采用随机区组设计,产量结果录入,数据如下:

数据见附件“one_way_anova_analyses.csv”
数据录入:
> library(reshape);library( agricolae )
> df<- read.table(file='one_way_anova_analyses.txt',header=T,sep='\t')
> df.2<-melt(df,id=c("Variety"))
> colnames(df.2)[2:3]<-c("Rep","y") #命名列
方差分析
> lmaov<-aov(y~Variety+Rep,data=df.2) #模型
> summary(lmaov)
Df Sum Sq Mean Sq F value Pr(>F)
Variety 5 52.38 10.476 78.764 3.17e-10 ***
Rep 3 2.68 0.893 6.717 0.00431 **
Residuals 15 2.00 0.133
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
> anova.tab(lmaov) #方差格式整理
Df Sum Sq Mean Sq F value Pr(>F)
Variety 5 52.38 10.476 78.764 3.17e-10 ***
Rep 3 2.68 0.893 6.717 0.00431 **
Residuals 15 2.00 0.133
Total 23 57.05
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
由方差分析可知,品种间和区组间均达到极显著水平,说明区组设计合理,降低了实验误差,提高了精确度。下面对品种进行多重比较。
多重比较
> LSD.test(lmaov,"Variety",group=F,console=T)
Study: lmaov ~ "Variety"
LSD t Test for y
Mean Square Error: 0.133
Variety, means and individual ( 95 %)CI
y std r LCL UCL Min Max
A 15.650 0.6557439 4 15.26134 16.03866 14.916.2
B 18.125 0.4272002 4 17.73634 18.51366 17.618.6
C 17.450 0.5744563 4 17.06134 17.83866 16.617.8
D 17.200 0.5830952 4 16.81134 17.58866 16.417.8
E 13.800 0.1825742 4 13.41134 14.18866 13.614.0
F 17.575 0.4924429 4 17.18634 17.96366 17.018.2
alpha: 0.05 ; Df Error: 15
Critical Value of t: 2.13145
Comparison between treatments means
Difference pvalue sig. LCL UCL
A - B -2.475 8.553878e-08 *** -3.0246495533 -1.9253504
A - C -1.800 4.424801e-06 *** -2.3496495533 -1.2503504
A - D -1.550 2.386356e-05 *** -2.0996495533 -1.0003504
A - E 1.8503.207722e-06 *** 1.3003504467 2.3996496
A - F -1.925 1.998570e-06 *** -2.4746495533 -1.3753504
B - C 0.6751.940896e-02 * 0.1253504467 1.2246496
B - D 0.9252.696626e-03 ** 0.3753504467 1.4746496
B - E 4.3253.975797e-11 *** 3.7753504467 4.8746496
B - F 0.550 4.987171e-02 * 0.0003504467 1.0996496
C - D 0.2503.476899e-01 -0.2996495533 0.7996496
C - E 3.6504.392580e-10 *** 3.1003504467 4.1996496
C - F -0.125 6.348707e-01 -0.6746495533 0.4246496
D - E 3.4001.181753e-09 *** 2.8503504467 3.9496496
D - F -0.375 1.664982e-01 -0.9246495533 0.1746496
E - F -3.775 2.737184e-10 *** -4.3246495533 -3.2253504
多重比较的结果如上表所示,B品种产量最高,显著高于其他品种。A品种和其他品种相比也达到极显著水平。