cement              package:AICcmodavg              R Documentation

_H_e_a_t _e_x_p_e_n_d_e_d _f_o_l_l_o_w_i_n_g _h_a_r_d_e_n_i_n_g _o_f _P_o_r_t_l_a_n_d _c_e_m_e_n_t.

_D_e_s_c_r_i_p_t_i_o_n:

     This data set illustrates the heat expended (calories) from
     mixtures of four different ingredients of Portland cement
     expressed as a percentage by weight.

_U_s_a_g_e:

     data(cement)

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

     A data frame with 13 observations on the following 5 variables.

     '_x_1' calcium aluminate

     '_x_2' tricalcium silicate

     '_x_3' tetracalcium alumino ferrite

     '_x_4' dicalcium silicate

     '_y' calories of heat per gram of cement following 180 days of
          hardening

_D_e_t_a_i_l_s:

     Burnham and Anderson (2002, p. 101) use this data set originally
     from Woods et al. (1932) to select among a set of multiple
     regression models.

_S_o_u_r_c_e:

     Burnham, K. P., Anderson, D. R. (2002) _Model Selection and
     Multimodel Inference: a practical information-theoretic approach_.
     Second edition. Springer: New York. 

     Woods, H., Steinour, H. H., Starke, H. R. (1932) Effect of
     composition of Portland cement on heat evolved during hardening.
     _Industrial and Engineering Chemistry_ *24*, 1207-1214.

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

     data(cement)
     ## maybe str(cement) ; plot(cement) ...

