pcX                   package:eba                   R Documentation

_P_a_i_r_e_d-_C_o_m_p_a_r_i_s_o_n _D_e_s_i_g_n _M_a_t_r_i_x

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

     Computes a paired-comparison design matrix.

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

     pcX(nstimuli)

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

nstimuli: number of stimuli in the paired-comparison design

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

     The design matrix can be used when fitting a Bradley-Terry-Luce
     (BTL) model by means of 'glm'.

_V_a_l_u_e:

     A matrix having '(nstimuli-1)*nstimuli/2' rows and 'nstimuli'
     columns.

_S_e_e _A_l_s_o:

     'OptiPt', 'glm'.

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

     data(celebrities)  # absolute choice frequencies
     btl <- OptiPt(celebrities)
     summary(btl)

     btl.glm <- glm(cbind(btl$y1, btl$y0) ~ pcX(9)[,-1] - 1, binomial)
     summary(btl.glm)  # BTL model does not fit these data!

