From: Dale Steele <Dale_Steele_at_brown.edu>

Date: Wed 11 Oct 2006 - 04:28:21 GMT

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Wed Oct 11 14:31:49 2006

Date: Wed 11 Oct 2006 - 04:28:21 GMT

I'm trying to write a small function (below) to compute Box & Cox
transformations of x for arbitrary values of lambda. I'd like to
specify a range of values for lamba (min,max,step) and am having trouble
getting the for loop to work. Suggestions?

Any pointers to resources for learning to write functions in R for neophyte programmers? Thanks. --Dale

boxcox <- function(x,min,max,step) {

lambda <- seq(min,max,step)

s <- length(lambda)

for (lambda in 1:s)

n <- nrow(x)

if(lambda ==0) xL <- log(x) else

xL <- ((x^lambda) - 1)/lambda

xLbar <- mean(xL)

t1 <- (-n/2)* log((1/n)*sum((xL - xLbar)^2))
t2 <- (lambda - 1)*sum(log(x))

l= t1 + t2

l

}

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Wed Oct 11 14:31:49 2006

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