agridat (version 1.16)

harville.lamb: Birth weight of lambs from different lines/sires

Description

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.

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

# NOT RUN {
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")

# }
# NOT RUN {
  if(require(lme4) & require(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 

  }
# }
# NOT RUN {
# }