cochran.bib {agridat} | R Documentation

## Multi-environment trial of corn, balanced incomplete block design

### Description

Balanced incomplete block design in corn

### Format

A data frame with 52 observations on the following 3 variables.

`loc`

  location/block, 13 levels

`gen`

  genotype/line, 13 levels

`yield`

  yield, pounds/plot

### Details

Incomplete block design. Each loc/block has 4 genotypes/lines. The blocks are planted at different locations.

Conducted in 1943 in North Carolina.

### Source

North Carolina Agricultural Experiment Station, United States Department of Agriculture.

### References

Cochran, W.G. and Cox, G.M. (1957), Experimental Designs, 2nd ed., Wiley and Sons, New York, p. 448.

### Examples

    data(cochran.bib)
    dat <- cochran.bib

    # Show the incomplete-block structure
    require(lattice)
    redblue <- colorRampPalette(c("firebrick", "lightgray", "#375997"))
    levelplot(yield~loc*gen, dat,
              col.regions=redblue,
              xlab="loc (block)", main="cochran.bib - incomplete blocks")

    with(dat, table(gen,loc))
    rowSums(as.matrix(with(dat, table(gen,loc))))
    colSums(as.matrix(with(dat, table(gen,loc))))

    m1 = aov(yield ~ gen + Error(loc), data=dat)
    summary(m1)

    require(nlme)
    m2 = lme(yield ~ -1 + gen, data=dat, random=~1|loc)

[Package agridat version 1.16 Index]