# BoxCoxTrans.default

0th

Percentile

##### Box-Cox Transformations

This class can be used to estimate a Box-Cox transformation and apply it to existing and future data

Keywords
utilities
##### Usage
BoxCoxTrans(y, ...)## S3 method for class 'default':
BoxCoxTrans(y, x = rep(1, length(y)),
fudge = 0.2, numUnique = 3, na.rm = FALSE, ...)## S3 method for class 'BoxCoxTrans':
predict(object, newdata, ...)
##### Arguments
y
a strictly positive numeric vector of data to be transformed
x
an optional dependent variable to be used in a liner model
fudge
a tolerance value: lambda values within +/-fudge will be coerced to 0 and within 1+/-fudge will be coerced to 1
numUnique
how many unique values should y have to estimate the transformation?
na.rm
a logical value indicating whether NA values should be stripped from y and x before the computation proceeds.
...
for BoxCoxTrans: options ot pass to boxcox. plotit should not be passed through. For predict.BoxCoxTrans, additional arguments are ignored.
object
an object of class BoxCoxTrans
newdata
a numeric vector of values to transform
##### Details

This function is basically a wrapper for the boxcox function in the MASS library. It can be used to estimate the transformation and apply it to new data.

If any(y <= 0)<="" code=""> or if length(unique(y)) < numUnique, lambda is not estimated and no transformation is applied.

##### Value

• BoxCoxTrans returns a list of class BoxCoxTrans with elements
• lambdaestimated transformation value
• fudgevalue of fudge
• nnumber of data points used to estimate lambda
• summarythe results of summary(y)
• ratiomax(y)/min(y)
• skewnesssample skewness statistic
• predict.BoxCoxTrans returns a numeric vector of transformed values

##### References

Box, G. E. P. and Cox, D. R. (1964) An analysis of transformations (with discussion). Journal of the Royal Statistical Society B, 26, 211-252.

boxcox, preProcess

##### Aliases
• BoxCoxTrans.default
• BoxCoxTrans
• predict.BoxCoxTrans
##### Examples
data(BloodBrain)

ratio <- exp(logBBB)
bc <- BoxCoxTrans(ratio)

bc

predict(bc, ratio[1:5])

ratio <- NA
bc2 <- BoxCoxTrans(ratio, bbbDescr\$tpsa, na.rm = TRUE)
bc2
Documentation reproduced from package caret, version 5.10-13, License: GPL-2

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