symbox

0th

Percentile

Boxplots for transformations to symmetry

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.

Keywords
hplot
Usage
symbox(x, powers=c(-1, -.5, 0, .5, 1), start=0)
Arguments
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 s
start
a constant to be added to x; after adding the start, all data values must be positive.
Value

  • as returned by boxplot.

References

Friendly, M. (2005) SAS System for Statistical Graphics, 2nd Edition. SAS Institute (In preparation).

See Also

boxplot, boxcox, box.cox

Aliases
  • symbox
Examples
symbox(Prestige$income)
Documentation reproduced from package car, version 1.2-10, License: GPL (>= 2)

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