| symbox {car} | R Documentation |
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, powers=c(-1, -.5, 0, .5, 1), start=0)
x |
a numeric vector. |
powers |
a vector of selected powers to which x is to be raised.
A power of 0 is taken to mean $log(x)$. Negative
powers are taken to mean $-x^p$, to preserve the order of the data.
For meaningful comparison of powers, 1 should be included
in the vector of powers. |
start |
a constant to be added to x; after adding the start, all data
values must be positive. |
as returned by boxplot.
Gregor Gorjanc, John Fox jfox@mcmaster.ca
Friendly, M. (2005) SAS System for Statistical Graphics, 2nd Edition. SAS Institute (In preparation).
symbox(Prestige$income)