gomez.fractionalfactorial {agridat} | R Documentation |
Rice fractional factorial experiment 1/2 2^6. Two reps with 2 blocks in each rep.
A data frame with 64 observations on the following 6 variables.
yield
grain yield in tons/ha
rep
replicate, 2 levels
block
block within rep, 2 levels
trt
treatment, levels (1) to abcdef
col
column position in the field
row
row position in the field
Grain yield from a 2^6 fractional factorial experiment in blocks of 16 plots each, with two replications.
Gomez has some inconsistencies. One example:
Page 171: treatment (1) in rep 1, block 2 and rep 2, block 1.
Page 172: treatment (1) in Rep 1, block 1 and rep 2, block 1.
This data uses the layout shown on page 171.
Gomez, K.A. and Gomez, A.A.. 1984, Statistical Procedures for Agricultural Research. Wiley-Interscience. Page 171-172.
Used with permission of Kwanchai Gomez.
data(gomez.fractionalfactorial) dat <- gomez.fractionalfactorial # trt abcdef has the highest yield # Gomez, Figure 4.8 if(require(desplot)){ desplot(yield~col*row, dat, # aspect unknown text=trt, shorten="none", show.key=FALSE, cex=1, main="gomez.fractionalfactorial - treatment & yield") } # 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) ## Not run: require(FrF2) aliases(m1) MEPlot(m1, select=3:8, main="gomez.fractionalfactorial - main effects plot") ## End(Not run)