Birth weight of lambs from different lines/sires

Usage

data("harville.lamb")

Format

A data frame with 62 observations on the following 4 variables.

line: genotype line number
sire: sire number
damage: dam age, class 1,2,3
weight: lamb birth weight

Details

Weight at birth of 62 lambs. There were 5 distinct lines.

Some sires had multiple lambs. Each dam had one lamb.

The age of the dam is a category: 1 (1-2 years), 2 (2-3 years) or 3 (over 3 years).

Note: Jiang, gives the data in table 1.2, but there is a small error. Jiang has a weight 9.0 for sire 31, line 3, age 3. The correct value is 9.5.

Source

David A. Harville and Alan P. Fenech (1985). Confidence Intervals for a Variance Ratio, or for Heritability, in an Unbalanced Mixed Linear Model. Biometrics, 41, 137-152. https://doi.org/10.2307/2530650

References

Jiming Jiang, Linear and Generalized Linear Mixed Models and Their Applications. Table 1.2.

Andre I. Khuri, Linear Model Methodology. Table 11.5. Page 368. https://books.google.com/books?id=UfDvCAAAQBAJ&pg=PA164

Daniel Gianola, Keith Hammond. Advances in Statistical Methods for Genetic Improvement of Livestock. Table 8.1, page 165.

Examples

if (FALSE) { # \dontrun{

library(agridat)
data(harville.lamb)
dat <- harville.lamb
dat <- transform(dat, line=factor(line), sire=factor(sire), damage=factor(damage))

library(lattice)
bwplot(weight ~ line, dat,
       main="harville.lamb",
       xlab="line", ylab="birth weights")

if(0){
  libs(lme4, lucid)
    
  m1 <- lmer(weight ~  -1 + line + damage + (1|sire), data=dat)
  summary(m1)
  vc(m1) # Khuri reports variances 0.5171, 2.9616
  ##      grp        var1 var2   vcov  sdcor
  ##     sire (Intercept) <NA> 0.5171 0.7191
  ## Residual        <NA> <NA> 2.962  1.721 
  }

} # }