bct {TeachingDemos} | R Documentation |
Box-Cox Transforms
Description
Computes the Box-Cox transform of the data for a given value of lambda. Includes the scaling factor.
Usage
bct(y, lambda)
Arguments
y |
Vector of data to be transformed. |
lambda |
Scalar exponent for transform (1 is linear, 0 is log). |
Details
bct
computes the Box-Cox family of transforms: y = (y^lambda -
1)/(lambda*gm^(lambda-1)), where gm is the geometric mean of the y's.
returns log(y)*gm when lambda equals 0.
Value
A vector of the same length as y with the corresponding transformed values.
Author(s)
Greg Snow 538280@gmail.com
See Also
vis.boxcox
, vis.boxcoxu
,
boxcox
in package MASS, other implementations in various
packages
Examples
y <- rlnorm(500, 3, 2)
par(mfrow=c(2,2))
qqnorm(y)
qqnorm(bct(y,1/2))
qqnorm(bct(y,0))
hist(bct(y,0))
[Package TeachingDemos version 2.13 Index]