R: Heights of Barley Plants

barleyHeights {gnm} | R Documentation

## Heights of Barley Plants

### Description

Average heights for 15 genotypes of barley recorded over 9 years.

### Usage

    barleyHeights

### Format

A data frame with 135 observations on the following 3 variables.

`height`

  average height over 4 replicates (cm)

`year`

  a factor with 9 levels `1974` to `1982`

`genotype`

  a factor with 15 levels `1:15`

### Source

Aastveit, A. H. \& Martens, H. (1986). ANOVA interactions interpreted by partial least squares regression. Biometrics, 42, 829–844.

### References

Chadoeuf, J \& Denis, J B (1991). Asymptotic variances for the multiplicative interaction model. J. App. Stat. 18(3), 331–353.

### Examples

    set.seed(1)
    ## Fit AMMI-1 model
    barleyModel <- gnm(height ~ year + genotype + Mult(year, genotype),
                       data = barleyHeights)

    ## Get row and column scores with se's
    gamma <- getContrasts(barleyModel, pickCoef(barleyModel, "[.]y"),
                          ref = "mean", scaleWeights = "unit")
    delta <- getContrasts(barleyModel, pickCoef(barleyModel, "[.]g"),
                          ref = "mean", scaleWeights = "unit")

    ## Corresponding CI's similar to Chadoeuf & Denis (1991) Table 8
    ## (allowing for change in sign)
    gamma[[2]][,1] + (gamma[[2]][,2]) %o% c(-1.96, 1.96)
    delta[[2]][,1] + (delta[[2]][,2]) %o% c(-1.96, 1.96)

    ## Multiplier of row and column scores
    height <- matrix(scale(barleyHeights$height, scale = FALSE), 15, 9)
    R <- height - outer(rowMeans(height), colMeans(height), "+")
    svd(R)$d[1]

[Package gnm version 1.0-8 Index]