Description Usage Format Details Source References Examples

Balanced lattice experiment in cotton

1 | ```
data("cochran.lattice")
``` |

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

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.

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.

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

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | ```
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)
``` |

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

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