A fitted model object, for example from lm or
aov, or a formula for alias.formula.
data
Optionally, a data frame to search for the objects
in the formula.
complete
Should information on complete aliasing be included?
partial
Should information on partial aliasing be included?
partial.pattern
Should partial aliasing be presented in a
schematic way? If this is done, the results are presented in a
more compact way, usually giving the deciles of the coefficients.
…
further arguments passed to or from other methods.
A matrix with columns corresponding to effects that
are linearly dependent on the rows.
Partial
The correlations of the estimable effects, with a zero
diagonal. An object of class "mtable" which has its own
print method.
Details
Although the main method is for class "lm", alias is
most useful for experimental designs and so is used with fits from
aov.
Complete aliasing refers to effects in linear models that cannot be estimated
independently of the terms which occur earlier in the model and so
have their coefficients omitted from the fit. Partial aliasing refers
to effects that can be estimated less precisely because of
correlations induced by the design.
Some parts of the "lm" method require recommended package
MASS to be installed.
References
Chambers, J. M., Freeny, A and Heiberger, R. M. (1992)
Analysis of variance; designed experiments.
Chapter 5 of Statistical Models in S
eds J. M. Chambers and T. J. Hastie, Wadsworth & Brooks/Cole.
# NOT RUN {<!-- % as it loads MASS -->
op <- options(contrasts = c("contr.helmert", "contr.poly"))
npk.aov <- aov(yield ~ block + N*P*K, npk)
alias(npk.aov)
options(op) # reset
# }