Burt                   package:car                   R Documentation

_F_r_a_u_d_u_l_e_n_t _D_a_t_a _o_n _I_Q_s _o_f _T_w_i_n_s _R_a_i_s_e_d _A_p_a_r_t

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

     The 'Burt' data frame has 27 rows and 4 columns. The ``data'' were
     simply (and notoriously) manufactured.

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

     data(Burt)

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

     This data frame contains the following columns:

     _I_Q_b_i_o IQ of twin raised by biological parents

     _I_Q_f_o_s_t_e_r IQ of twin raised by foster parents

     _c_l_a_s_s A factor with levels (note: out of order): 'high'; 'low';
          'medium'.

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

     Burt, C. (1966)  The genetic determination of differences in
     intelligence:  A study of monozygotic twins reared together and
     apart.  _British Journal of Psychology_ *57*, 137-153.

