symbox
first transforms x
to each of a series
of selected powers, with each transformation standardized to mean 0 and
standard deviation 1. The results are then displayed side-by-side in boxplots, permiting
a visual assessment of which power makes the distribution reasonably symmetric.symbox(x, ...)
"symbox"(formula, data=NULL, subset, na.action=NULL, ylab, ...)
"symbox"(x, powers = c(-1, -0.5, 0, 0.5, 1), start=0,
trans=bcPower, xlab="Powers", ylab, ...)
lm
).ylab
is missing, a label will be supplied.x
is to be raised.
For meaningful comparison of powers, 1
should be included
in the vector of powers.x
.boxplot
.Fox, J. and Weisberg, S. (2011) An R Companion to Applied Regression, Second Edition. Sage.
boxplot
, boxcox
, bcPower
, yjPower
symbox(~ income, data=Prestige)
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