# BoxCox: Box Cox Transformation In DescTools: Tools for Descriptive Statistics

 BoxCox R Documentation

## Box Cox Transformation

### Description

`BoxCox()` returns a transformation of the input variable using a Box-Cox transformation.
`BoxCoxInv()` reverses the transformation.

### Usage

```BoxCox(x, lambda)
BoxCoxInv(x, lambda)
```

### Arguments

 `x` a numeric vector `lambda` transformation parameter

### Details

The Box-Cox transformation is given by

f(x;λ)=(x^λ - 1)/λ, if λ not 0, log(x), otherwise

### Value

a numeric vector of the same length as x.

### Note

These two functions are borrowed from `library(forecast)`.

### Author(s)

Rob J Hyndman <rob.hyndman@monash.edu>

### References

Box, G. E. P. and Cox, D. R. (1964) An analysis of transformations. JRSS B 26 211–246.

Use `BoxCoxLambda` or `boxcox` in `library(MASS)` to find optimal lambda values.

### Examples

```# example by Greg Snow
x <- rlnorm(500, 3, 2)

par(mfrow=c(2,2))
qqnorm(x, main="Lognormal")
qqnorm(BoxCox(x, 1/2), main="BoxCox(lambda=0.5)")
qqnorm(BoxCox(x, 0), main="BoxCox(lambda=0)")

PlotFdist(BoxCox(x, 0))

bx <- BoxCox(x, lambda = BoxCoxLambda(x) )
```

DescTools documentation built on Oct. 23, 2022, 1:07 a.m.