harville.lamb {agridat} | R Documentation

## 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.

### 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. http://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

    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

      }

    ## End(Not run)

[Package agridat version 1.16 Index]