\HeaderA{whiteside}{House Insulation: Whiteside's Data}{whiteside}
\keyword{datasets}{whiteside}
\begin{Description}\relax
Mr Derek Whiteside of the UK Building Research Station recorded the
weekly gas consumption and average external temperature at his own
house in south-east England for two heating seasons, one of 26 weeks
before, and one of 30 weeks after cavity-wall insulation was
installed. The object of the exercise was to assess the effect of the
insulation on gas consumption.
\end{Description}
\begin{Usage}
\begin{verbatim}
whiteside
\end{verbatim}
\end{Usage}
\begin{Format}\relax
The \code{whiteside} data frame has 56 rows and 3 columns.:
\describe{
\item[\code{Insul}] A factor, before or after insulation.

\item[\code{Temp}] Purportedly the average outside temperature in degrees Celsius. (These
values is far too low for any 56-week period in the 1960s in
South-East England. It might be the weekly average of daily minima.)

\item[\code{Gas}] The weekly gas consumption in 1000s of cubic feet.
}
\end{Format}
\begin{Source}\relax
A data set collected in the 1960s by Mr Derek Whiteside of the
UK~Building Research Station. Reported by

Hand, D. J., Daly, F., McConway, K., Lunn, D. and Ostrowski, E. eds (1993)
\emph{A Handbook of Small Data Sets.}
Chapman \& Hall, p. 69.
\end{Source}
\begin{References}\relax
Venables, W. N. and Ripley, B. D. (2002)
\emph{Modern Applied Statistics with S.} Fourth edition.  Springer.
\end{References}
\begin{Examples}
\begin{ExampleCode}
require(lattice)
xyplot(Gas ~ Temp | Insul, whiteside, panel =
  function(x, y, ...) {
    panel.xyplot(x, y, ...)
    panel.lmline(x, y, ...)
  }, xlab = "Average external temperature (deg. C)",
  ylab = "Gas consumption  (1000 cubic feet)", aspect = "xy",
  strip = function(...) strip.default(..., style = 1))

gasB <- lm(Gas ~ Temp, whiteside, subset = Insul=="Before")
gasA <- update(gasB, subset = Insul=="After")
summary(gasB)
summary(gasA)
gasBA <- lm(Gas ~ Insul/Temp - 1, whiteside)
summary(gasBA)

gasQ <- lm(Gas ~ Insul/(Temp + I(Temp^2)) - 1, whiteside)
summary(gasQ)$coef

gasPR <- lm(Gas ~ Insul + Temp, whiteside)
anova(gasPR, gasBA)
options(contrasts = c("contr.treatment", "contr.poly"))
gasBA1 <- lm(Gas ~ Insul*Temp, whiteside)
summary(gasBA1)$coef
\end{ExampleCode}
\end{Examples}