# becker.chicken: Mating crosses of chickens In agridat: Agricultural Datasets

## Description

Mating crosses of chickens

## Usage

 `1` ```data("becker.chicken") ```

## Format

A data frame with 45 observations on the following 3 variables.

`male`

male parent

`female`

female parent

`weight`

weight (g) at 8 weeks

## Details

From a large flock White Rock chickens, five male sires were chosen and mated to each of three female dams, producing 3 female progeny. The data are body weights at eight weeks of age.

Becker (1984) used these data to demonstrate the calculation of heritability.

## Source

Walter A. Becker (1984). Manual of Quantitative Genetics, 4th ed. Page 83.

None

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35``` ```data(becker.chicken) dat <- becker.chicken if(require(lattice)){ dotplot(weight ~ female, data=dat, group=male, main="becker.chicken - progeny weight by M*F", xlab="female parent",ylab="progeny weight", auto.key=list(columns=5)) } ## Not run: # Sums match Becker sum(dat\$weight) aggregate(weight ~ male + female, dat, FUN=sum) # Variance components require(lme4) require(lucid) m1 <- lmer(weight ~ (1|male) + (1|female), data=dat) as.data.frame(lme4::VarCorr(m1)) ## grp var1 var2 vcov sdcor ## 1 female (Intercept) 1095.6296 33.10030 ## 2 male (Intercept) 776.7543 27.87031 ## 3 Residual 5524.4000 74.32631 # Calculate heritabilities s2m <- 776 # variability for males s2f <- 1095 # variability for females s2w <- 5524 # variability within crosses vp <- s2m + s2f + s2w # 7395 4*s2m/vp # .42 male heritability 4*s2f/vp # .59 female heritability ## End(Not run) ```

agridat documentation built on May 2, 2019, 4:01 p.m.