Arthritis                package:vcd                R Documentation

_A_r_t_h_r_i_t_i_s _T_r_e_a_t_m_e_n_t _D_a_t_a

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

     Data from Koch & Edwards (1988) from a double-blind clinical trial
     investigating a new treatment for rheumatoid arthritis.

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

     data(Arthritis)

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

     A data frame with 84 observations and 5 variables.

     _I_D patient ID.

     _T_r_e_a_t_m_e_n_t factor indicating treatment (Placebo, Treated).

     _S_e_x factor indicating sex (Female, Male).

     _A_g_e age of patient.

     _I_m_p_r_o_v_e_d ordered factor indicating treatment outcome (None, Some,
          Marked).

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

     Michael Friendly (2000), Visualizing Categorical Data: <URL:
     http://euclid.psych.yorku.ca/ftp/sas/vcd/catdata/arthrit.sas>

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

     G. Koch & S. Edwards (1988), Clinical efficiency trials with
     categorical data. In K. E. Peace (ed.), _Biopharmaceutical
     Statistics for Drug Development_, 403-451. Marcel Dekker, New
     York.

     M. Friendly (2000), _Visualizing Categorical Data_. SAS Institute,
     Cary, NC.

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

     data(Arthritis)

     ## construct a table of interest using xtabs() or structable()
     ## via formula
     structable(Sex ~ Treatment + Improved, data = Arthritis)

     ## via default interface
     attach(Arthritis)
     structable(Treatment, Sex, Improved)
     detach(Arthritis)

     ## via xtabs and ftable
     ftable(xtabs(~Treatment + Improved + Sex, data = Arthritis))

