| kiwishade {DAAG} | R Documentation |
The kiwishade data frame has 48 rows and 4 columns.
The data are from a designed experiment that
compared different kiwifruit shading treatments.
There are four vines in each plot, and four plots (one for each of four
treatments: none, Aug2Dec, Dec2Feb, and Feb2May) in each of three blocks
(locations: west, north, east). Each
plot has the same number of vines, each block has the same number of
plots, with each treatment occurring the same number of times.
kiwishade
This data frame contains the following columns:
east.Aug2Dec,
east.Dec2Feb, east.Feb2May,
east.none, north.Aug2Dec,
north.Dec2Feb, north.Feb2May,
north.none, west.Aug2Dec,
west.Dec2Feb, west.Feb2May,
west.none east, north, west none no shading, Aug2Dec August - December,
Dec2Feb December - February, Feb2May February - MayThe northernmost plots were grouped together because they were similarly affected by shading from the sun in the north. For the remaining two blocks shelter effects, whether from the west or from the east, were thought more important.
Snelgar, W.P., Manson. P.J., Martin, P.J. 1992. Influence of time of shading on flowering and yield of kiwifruit vines. Journal of Horticultural Science 67: 481-487.
Maindonald J H 1992. Statistical design, analysis and presentation issues. New Zealand Journal of Agricultural Research 35: 121-141.
print("Data Summary - Example 2.2.1")
attach(kiwishade)
kiwimeans <- aggregate(yield, by=list(block, shade), mean)
names(kiwimeans) <- c("block","shade","meanyield")
kiwimeans[1:4,]
pause()
print("Multilevel Design - Example 9.3")
kiwishade.aov <- aov(yield ~ shade+Error(block/shade),data=kiwishade)
summary(kiwishade.aov)
pause()
sapply(split(yield, shade), mean)
pause()
kiwi.table <- t(sapply(split(yield, plot), as.vector))
kiwi.means <- sapply(split(yield, plot), mean)
kiwi.means.table <- matrix(rep(kiwi.means,4), nrow=12, ncol=4)
kiwi.summary <- data.frame(kiwi.means, kiwi.table-kiwi.means.table)
names(kiwi.summary)<- c("Mean", "Vine 1", "Vine 2", "Vine 3", "Vine 4")
kiwi.summary
mean(kiwi.means) # the grand mean (only for balanced design)
require(nlme)
kiwishade.lme <- lme(fixed = yield ~ shade, random = ~ 1 | block/plot,
data=kiwishade)
res <- residuals(kiwishade.lme)
hat <- fitted(kiwishade.lme) # By default fitted(kiwishade.lme, level=2)
coplot(res ~ hat | kiwishade$block, pch=16, columns=3,
xlab= "Fitted", ylab="Residuals")
res <- residuals(kiwishade.lme)
hat <- fitted(kiwishade.lme, level=0) # shade effects only
unique(hat) # There are just four distinct values, one per treatment
coplot(res ~ hat | kiwishade$block, pch=16, columns=3,
xlab="Fitted", ylab="Residuals")
n.omit <- 2
take <- rep(TRUE, 48)
take[sample(1:48,2)] <- FALSE
kiwishade.lme <- lme(yield ~ shade, data = kiwishade,
random = ~1 | block/plot, subset=take)
VarCorr(kiwishade.lme)[4, 1] # Plot component of variance
VarCorr(kiwishade.lme)[4, 1] # Vine component of variance
detach(kiwishade)