R: Data for an analysis in split-plot

plots {agricolae} | R Documentation

## Data for an analysis in split-plot

### Description

Experimental data in blocks, factor A in plots and factor B in sub-plots.

### Usage

    data(plots)

### Format

A data frame with 18 observations on the following 5 variables.

`block`

  a numeric vector

`plot`

  a factor with levels `p1` `p2` `p3` `p4` `p5` `p6`

`A`

  a factor with levels `a1` `a2`

`B`

  a factor with levels `b1` `b2` `b3`

`yield`

  a numeric vector

### Source

International Potato Center. CIP

### Examples

    library(agricolae)
    data(plots)
    str(plots)
    plots[,1] <-as.factor(plots[,1])
    # split-plot analysis
    model <- aov(yield ~ block + A + Error(plot)+ B + A:B, data=plots)
    summary(model)
    b<-nlevels(plots$B)
    a<-nlevels(plots$A)
    r<-nlevels(plots$block)
    dfa <- df.residual(model$plot)
    Ea <-deviance(model$plot)/dfa
    dfb <- df.residual(model$Within)
    Eb <-deviance(model$Within)/dfb
    Eab <- (Ea +(b-1)*Eb)/(b*r)
    # Satterthwaite
    dfab<-(Ea +(b-1)*Eb)^2/(Ea^2/dfa +((b-1)*Eb)^2/dfb)
    # Comparison A, A(b1), A(b2), A(b3)
    comparison1 <-with(plots,LSD.test(yield,A,dfa,Ea))
    comparison2 <-with(plots,LSD.test(yield[B=="b1"],A[B=="b1"],dfab,Eab))
    comparison3 <-with(plots,LSD.test(yield[B=="b2"],A[B=="b2"],dfab,Eab))
    comparison4 <-with(plots,LSD.test(yield[B=="b3"],A[B=="b3"],dfab,Eab))
    # Comparison B, B(a1), B(a2)
    comparison5 <-with(plots,LSD.test(yield,B,dfb,Eb))
    comparison6 <-with(plots,LSD.test(yield[A=="a1"],B[A=="a1"],dfb,Eb))
    comparison7 <-with(plots,LSD.test(yield[A=="a2"],B[A=="a2"],dfb,Eb))

[Package agricolae version 1.2-6 Index]