whiteside                package:MASS                R Documentation

_H_o_u_s_e _I_n_s_u_l_a_t_i_o_n: _W_h_i_t_e_s_i_d_e'_s _D_a_t_a

_D_e_s_c_r_i_p_t_i_o_n:

     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.

_U_s_a_g_e:

     whiteside

_F_o_r_m_a_t:

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

     '_I_n_s_u_l' A factor, before or after insulation.

     '_T_e_m_p' 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.)

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

_S_o_u_r_c_e:

     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.

_R_e_f_e_r_e_n_c_e_s:

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

_E_x_a_m_p_l_e_s:

     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)
     coef(summary(gasQ))

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

