man/Acetylene.Rd

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/data.R
\docType{data}
\name{Acetylene}
\alias{Acetylene}
\title{Acetylene Data}
\format{
A data frame with 16 observations on the following 4 variables.
\describe{ 
 \item{\code{yield}}{conversion percentage yield of acetylene}
 \item{\code{temp}}{reactor temperature (celsius)} 
 \item{\code{ratio}}{H2 to N-heptone ratio} 
 \item{\code{time}}{contact time (sec)} 
}
}
\source{
SAS documentation example for \code{PROC REG}, \emph{Ridge
Regression for Acetylene Data}.
}
\description{
The data consist of measures of \code{yield} of a chemical manufacturing
process for acetylene in relation to numeric parameters.
}
\details{
Marquardt and Snee (1975) used these data to illustrate ridge regression in
a model containing quadratic and interaction terms, particularly the need to
center and standardize variables appearing in high-order terms.

Typical models for these data include the interaction of \code{temp:ratio},
and a squared term in \code{temp}
}
\examples{

data(Acetylene)

# naive model, not using centering
amod0 <- lm(yield ~ temp + ratio + time + I(time^2) + temp:time, data=Acetylene)

y <- Acetylene[,"yield"]
X0 <- model.matrix(amod0)[,-1]

lambda <- c(0, 0.0005, 0.001, 0.002, 0.005, 0.01)
aridge0 <- ridge(y, X0, lambda=lambda)

traceplot(aridge0)
traceplot(aridge0, X="df")
pairs(aridge0, radius=0.2)


}
\references{
Marquardt, D.W., and Snee, R.D. (1975), "Ridge Regression in
Practice," \emph{The American Statistician}, \bold{29}, 3-20.

Marquardt, D.W. (1980), "A Critique of Some Ridge Regression Methods:
Comment," \emph{Journal of the American Statistical Association}, Vol. 75,
No. 369 (Mar., 1980), pp. 87-91
}
\keyword{datasets}