whiteside                package:MASS                R Documentation

House Insulation: Whiteside's Data

Description:

     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.

Usage:

     data(whiteside)

Format:

     The 'whiteside' data frame has 56 rows and 3 columns.:

     'Insul' A factor, before or after insulation.

     '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.)

     'Gas' The weekly gas consumption in 1000s of cubic feet.

Source:

     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) _A Handbook of Small Data Sets._ Chapman & Hall, p. 69.

References:

     Venables, W. N. and Ripley, B. D. (2002) _Modern Applied
     Statistics with S._ Fourth edition.  Springer.

Examples:

     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

