agridat (version 1.8.1)

jenkyn.mildew: Yields from treatment for mildew control

Description

Yields from treatment for mildew control

source

Norman Draper and Irwin Guttman (1980), "Incorporating Overlap Effects from Neighboring Units into Response Surface Models". Appl Statist, 29, 128--134.

Details

There were four spray treatments: 0 (none), 1 (early), 2 (late), R (repeated). Each treatment occurs once between each f the 9 ordered pairs of the other treatments. The first and last plot are not assigned to a block.

References

Maria Durban, Christine Hackett, Iain Currie. Blocks, Trend and Interference in Field Trials.

Examples

dat <- jenkyn.mildew

require(lattice)
bwplot(yield ~ trt, dat)

# Residuals from treatment model show obvious spatial trends
m0 <- lm(yield ~ trt, dat)
xyplot(resid(m0)~plot, dat)

# The blocks explain most of the variation
m1 <- lm(yield ~ trt + block, dat)
xyplot(resid(m1)~plot, dat)