https://github.com/cran/lattice
Tip revision: 01ca7cfc46c13ce55a9ded37d1feafd0edde1a42 authored by Deepayan Sarkar on 08 January 2013, 00:00:00 UTC
version 0.20-13
version 0.20-13
Tip revision: 01ca7cf
ethanol.Rd
\name{H_ethanol}
\alias{ethanol}
\docType{data}
\title{ Engine exhaust fumes from burning ethanol }
\description{
Ethanol fuel was burned in a single-cylinder engine. For various
settings of the engine compression and equivalence ratio, the
emissions of nitrogen oxides were recorded.
}
\usage{ethanol}
\format{
A data frame with 88 observations on the following 3 variables.
\describe{
\item{NOx}{Concentration of nitrogen oxides (NO and NO2) in
micrograms/J.}
\item{C}{Compression ratio of the engine.}
\item{E}{Equivalence ratio--a measure of the richness of the air and
ethanol fuel mixture.}
}
}
\source{
Brinkman, N.D. (1981) Ethanol Fuel---A Single-Cylinder Engine Study of
Efficiency and Exhaust Emissions. \emph{SAE transactions},
\bold{90}, 1410--1424.
}
\author{
Documentation contributed by Kevin Wright.
}
\references{
Cleveland, William S. (1993) \emph{Visualizing Data}. Hobart Press,
Summit, New Jersey.
}
\examples{
## Constructing panel functions on the fly
EE <- equal.count(ethanol$E, number=9, overlap=1/4)
xyplot(NOx ~ C | EE, data = ethanol,
prepanel = function(x, y) prepanel.loess(x, y, span = 1),
xlab = "Compression ratio", ylab = "NOx (micrograms/J)",
panel = function(x, y) {
panel.grid(h=-1, v= 2)
panel.xyplot(x, y)
panel.loess(x,y, span=1)
},
aspect = "xy")
# Wireframe loess surface fit. See Figure 4.61 from Cleveland.
require(stats)
with(ethanol, {
eth.lo <- loess(NOx ~ C * E, span = 1/3, parametric = "C",
drop.square = "C", family="symmetric")
eth.marginal <- list(C = seq(min(C), max(C), length.out = 25),
E = seq(min(E), max(E), length.out = 25))
eth.grid <- expand.grid(eth.marginal)
eth.fit <- predict(eth.lo, eth.grid)
wireframe(eth.fit ~ eth.grid$C * eth.grid$E,
shade=TRUE,
screen = list(z = 40, x = -60, y=0),
distance = .1,
xlab = "C", ylab = "E", zlab = "NOx")
})
}
\keyword{datasets}