gomez.multilocsplitplot {agridat} R Documentation

## Multi-environment trial of rice, split-plot design

### Description

Grain yield was measured at 3 locations with 2 reps per location. Within each rep, the main plot was 6 nitrogen fertilizer treatments and the sub plot was 2 rice varieties.

### Format

A data frame with 108 observations on the following 5 variables.

`loc`

location, 3 levels

`nitro`

nitrogen in kg/ha

`rep`

replicate, 2 levels

`gen`

genotype, 2 levels

`yield`

yield, kg/ha

Used with permission of Kwanchai Gomez.

### Source

Gomez, K.A. and Gomez, A.A.. 1984, Statistical Procedures for Agricultural Research. Wiley-Interscience. Page 339.

### Examples

```
library(agridat)

data(gomez.multilocsplitplot)
dat <- gomez.multilocsplitplot
dat\$nf <- factor(dat\$nitro)

# Gomez figure 8.3
libs(lattice)
xyplot(yield~nitro, dat, group=loc, type=c('p','smooth'), auto.key=TRUE,
main="gomez.multilocsplitplot")

# AOV
# Be careful to use the right stratum, 'nf' appears in both strata.
# Still not quite the same as Gomez table 8.21
t1 <- terms(yield ~ loc * nf * gen + Error(loc:rep:nf),
"Error", keep.order=TRUE)
m1 <- aov(t1, data=dat)
summary(m1)

## Not run:
# F values are somewhat similar to Gomez Table 8.21
libs(lme4)
m2 <- lmer(yield ~ loc*nf*gen + (1|loc/rep/nf), dat)
anova(m2)
## Analysis of Variance Table
##            Df   Sum Sq  Mean Sq F value
## loc         2   117942    58971  0.1525
## nf          5 72841432 14568286 37.6777
## gen         1  7557570  7557570 19.5460
## loc:nf     10 10137188  1013719  2.6218
## loc:gen     2  4270469  2135235  5.5223
## nf:gen      5  1501767   300353  0.7768
## loc:nf:gen 10  1502273   150227  0.3885

## End(Not run)

```

[Package agridat version 1.18 Index]