pneumo                 package:VGAM                 R Documentation

_P_n_e_u_m_o_c_o_n_i_o_s_i_s _a_m_o_n_g_s_t _a _g_r_o_u_p _o_f _c_o_a_l_m_i_n_e_r_s

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

     The 'pneumo' data frame has 8 rows and 4 columns. Exposure time is
     explanatory, and there are 3 ordinal response variables.

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

     data(pneumo)

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

     This data frame contains the following columns:

     _e_x_p_o_s_u_r_e._t_i_m_e a numeric vector, in years

     _n_o_r_m_a_l a numeric vector, counts

     _m_i_l_d a numeric vector, counts

     _s_e_v_e_r_e a numeric vector, counts

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

     These were collected from coalface workers. In the original data
     set, the two most severe categories were combined.

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

     Ashford, J.R., 1959. An approach to the analysis of data for
     semi-quantal responses in biological assay. _Biometrics_, *15*,
     573-581.

_R_e_f_e_r_e_n_c_e_s:

     McCullagh, P. and Nelder, J. A. (1989) _Generalized Linear
     Models_, 2nd ed. London: Chapman & Hall.

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

     data(pneumo)

     # Fit the proportional odds model, p.179, in McCullagh and Nelder (1989) 
     pneumo = transform(pneumo, let=log(exposure.time))
     vglm(cbind(normal,mild,severe) ~ let, 
          cumulative(parallel=TRUE, reverse=TRUE), pneumo)

