

whiteside(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 exter-
     nal 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 con-
     sumption.

_A_r_g_u_m_e_n_t_s_:

   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 Eng-
          land. It might be the weekly average of daily min-
          ima.)

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

_F_o_r_m_a_t_:

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

_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

