barleyHeights: Heights of Barley Plants

In gnm: Generalized Nonlinear Models

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

References

Chadoeuf, J and 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 and 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]

gnm documentation built on Sept. 16, 2023, 5:06 p.m.