agridat (version 1.12)

gomez.fractionalfactorial: Rice fractional factorial experiment

Description

A 1/2 fractional factorial experiment with 6 treatments. Two reps with 2 blocks in each rep.

Format

A data frame with 64 observations on the following 6 variables.

yield

Grain yield in tons/ha

rep

Replicate factor, 2 levels

block

Block factor within rep, 2 levels

trt

Treatment factor, levels (1) to abcdef

x

Column position in the field

y

Row position in the field

Details

Note: In Gomez, page 171 has (for example) treatment (1) in Rep 1, Block 2 and Rep 2, Block 1. Page 172 has treatment (1) in Block 1 of both reps. This data uses the layout shown on page 171.

Examples

# NOT RUN {
data(gomez.fractionalfactorial)
dat <- gomez.fractionalfactorial

# trt abcdef has the highest yield
# Gomez, Figure 4.8
desplot(yield~x*y, dat, main="gomez.fractionalfactorial - treatment & yield",
        text=trt, shorten="none", show.key=FALSE, cex=1)


# Split treatment into individual factors
dat <- transform(dat,
                 a = -1 + 2 * grepl('a',trt),
                  b = -1 + 2 * grepl('b',trt),
                 c = -1 + 2 * grepl('c',trt),
                 d = -1 + 2 * grepl('d',trt),
                 e = -1 + 2 * grepl('e',trt),
                 f = -1 + 2 * grepl('f',trt))

# Gomez table 4.24, trt SS totalled together.
# Why didn't Gomez nest block within rep?
m0 <- lm(yield ~ rep * block + trt, dat)
anova(m0)

# Gomez table 4.24, trt SS split apart
m1 <- lm(yield ~ rep * block + (a+b+c+d+e+f)^3, dat)
anova(m1)

if(require(FrF2)){
  aliases(m1)
  MEPlot(m1, select=3:8,
         main="gomez.fractionalfactorial - main effects plot")
  #IAPlot(m1, select=3:8)
}

# }