summary.aov
Summarize an Analysis of Variance Model
Summarize an analysis of variance model.
 Keywords
 models, regression
Usage
"summary"(object, intercept = FALSE, split, expand.split = TRUE, keep.zero.df = TRUE, ...)
"summary"(object, ...)
Arguments
 object
 An object of class
"aov"
or"aovlist"
.  intercept
 logical: should intercept terms be included?
 split
 an optional named list, with names corresponding to terms in the model. Each component is itself a list with integer components giving contrasts whose contributions are to be summed.
 expand.split
 logical: should the split apply also to interactions involving the factor?
 keep.zero.df
 logical: should terms with no degrees of freedom be included?
 ...
 Arguments to be passed to or from other methods,
for
summary.aovlist
including those forsummary.aov
.
Value

An object of class
c("summary.aov", "listof")
or
"summary.aovlist"
respectively.For fits with a single stratum the result will be a list of
ANOVA tables, one for each response (even if there is only one response):
the tables are of class "anova"
inheriting from class
"data.frame"
. They have columns "Df"
, "Sum Sq"
,
"Mean Sq"
, as well as "F value"
and "Pr(>F)"
if
there are nonzero residual degrees of freedom. There is a row for
each term in the model, plus one for "Residuals"
if there
are any.For multistratum fits the return value is a list of such summaries,
one for each stratum.
Note
The use of expand.split = TRUE
is little tested: it is always
possible to set it to FALSE
and specify exactly all
the splits required.
See Also
Examples
library(stats)
## For a simple example see example(aov)
# Cochran and Cox (1957, p.164)
# 3x3 factorial with ordered factors, each is average of 12.
CC < data.frame(
y = c(449, 413, 326, 409, 358, 291, 341, 278, 312)/12,
P = ordered(gl(3, 3)), N = ordered(gl(3, 1, 9))
)
CC.aov < aov(y ~ N * P, data = CC , weights = rep(12, 9))
summary(CC.aov)
# Split both main effects into linear and quadratic parts.
summary(CC.aov, split = list(N = list(L = 1, Q = 2),
P = list(L = 1, Q = 2)))
# Split only the interaction
summary(CC.aov, split = list("N:P" = list(L.L = 1, Q = 2:4)))
# split on just one var
summary(CC.aov, split = list(P = list(lin = 1, quad = 2)))
summary(CC.aov, split = list(P = list(lin = 1, quad = 2)),
expand.split = FALSE)
Community examples
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