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 26 weeks before, and 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:

     data(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.

_E_x_a_m_p_l_e_s:

     data(whiteside)
     coplot(Gas ~ Temp | Insul, whiteside, panel = 
       function(x, y, ...) {
          points(x, y, ...)
          abline(lm(y ~ x))
       }, xlab = "Average external temperature (deg. C)",
       ylab = "Gas consumption  (1000 cubic feet)")

     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

