cochran.lattice {agridat} | R Documentation

## Balanced lattice experiment in cotton

### Description

Balanced lattice experiment in cotton

### Usage

    data("cochran.lattice")

### Format

A data frame with 80 observations on the following 5 variables.

`y`

  percent of affected flower buds

`rep`

  replicate

`row`

  row

`col`

  column

`trt`

  treatment factor

### Details

The experiment is a balanced lattice square with 16 treatments in a 4x4 layout in each of 5 replicates. The treatments were applied to cotton plants. Each plot was ten rows wide by 70 feet long (about 1/18 of an acre). (Estimated plot width is 34.5 feet.) Data were collected from the middle 4 rows. The data are the percentages of squares showing attack by boll weevils. A 'square' is the name given to a young flower bud.

The plot orientation is not clear.

### Source

William G. Cochran, Gertrude M. Cox. Experimental Designs, 2nd Edition. Page 490.

Originally from: F. M. Wadley (1946). Incomplete block designs in insect population problems. J. Economic Entomology, 38, 651–654.

### References

Walter Federer. Combining Standard Block Analyses With Spatial Analyses Under a Random Effects Model. Cornell Univ Tech Report BU-1373-MA. http://hdl.handle.net/1813/31971

### Examples

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

    if(require(desplot)){
      desplot(y~row*col|rep, dat,
              text=trt, # aspect unknown, should be 2 or .5
              main="cochran.lattice")
    }

    ## Not run:
      # Random rep,row,column model often used by Federer
      require(lme4)
      dat <- transform(dat, rowf=factor(row), colf=factor(col))
      m1 <-  lmer(y ~ trt + (1|rep) + (1|rep:row) + (1|rep:col), data=dat)
      summary(m1)

    ## End(Not run)

[Package agridat version 1.16 Index]