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. https://hdl.handle.net/1813/31971

Examples

if (FALSE) { # \dontrun{

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

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


# Random rep,row,column model often used by Federer
libs(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)

} # }