The input power value is rounded to the nearest integer or fractional powers, \(\pm 1/3, 1/2\).
The function is presently designed just for display purposes.
Arguments
- p
A numeric power, for use as a transformation of a response, y, of the form \(y^p\),
where p=0 is interpreted to mean \(log(y)\)
Value
a named list of two elements: power, the ladder-of-power value, and
name, the name for the transformation
Details
In use, the transformation via the ladder of powers usually attaches a minus sign to
the transformation when the power < 0, so that the order of the response values
are preserved under the transformation. Thus, a result of power = -0.5 is interpreted
to mean \(-1 / \sqrt{y}\).
References
Tukey, J. W. (1977). Exploratory Data Analysis, Reading MA: Addison-Wesley.
Examples
ladder_power(0.6)
#> $power
#> [1] 0.5
#>
#> $name
#> [1] "square root"
#>
ladder_power(-0.6)
#> $power
#> [1] -0.5
#>
#> $name
#> [1] "reciprocal root"
#>
