logtrafo {trafo}

Log transformation for linear models

Description

The function transforms the dependent variable of a linear model using the Log transformation. The Log transformation is only defined for positive response values. In case the response contains zero or negative values a shift is automatically added such that y + shift > 0.

Usage

logtrafo(object)

Arguments

object

an object of type lm.

Value

An object of class trafo. Methods such as as.data.frame.trafo and print.trafo can be used for this class.

References

Box GEP, Cox DR (1964). An Analysis of Transformations. Journal of the Royal Statistical Society B, 26(2), 211-252.

Examples

# Load data
data("cars", package = "datasets")

# Fit linear model
lm_cars <- lm(dist ~ speed, data = cars)

# Transform dependent variable 
logtrafo(object = lm_cars)