SIMS                package:SASmixed                R Documentation

_S_e_c_o_n_d _I_n_t_e_r_n_a_t_i_o_n_a_l _M_a_t_h_e_m_a_t_i_c_s _S_t_u_d_y _d_a_t_a

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

     The 'SIMS' data frame has 3691 rows and 3 columns.

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

     This data frame contains the following columns:

     _P_r_e_t_o_t a numeric vector giving the student's pre-test total score

     _G_a_i_n a numeric vector giving gains from pre-test to the final test

     _C_l_a_s_s an ordered factor giving the student's class

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

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

     Littel, R. C., Milliken, G. A., Stroup, W. W., and Wolfinger, R.
     D. (1996), _SAS System for Mixed Models_, SAS Institute (section
     7.2.2)

     Kreft, I. G. G., De Leeuw, J. and Var Der Leeden, R. (1994),
     ``Review of five multilevel analysis programs: BMDP-5V, GENMOD,
     HLM, ML3, and VARCL'', _American Statistician_, *48*, 324-335.

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

     str(SIMS)
     if (require("lme4", quietly = TRUE, character = TRUE)) {
       options(contrasts = c(unordered = "contr.SAS", ordered = "contr.poly"))
       ## compare to output 7.4, p. 262
       print(fm1SIMS <- lmer(Gain ~ Pretot + (Pretot | Class), data = SIMS,
                     control = list(msVerbose = TRUE)))
       print(anova(fm1SIMS))
     }

