Chem97                package:mlmRev                R Documentation

_S_c_o_r_e_s _o_n _A-_l_e_v_e_l _C_h_e_m_i_s_t_r_y _i_n _1_9_9_7

_D_e_s_c_r_i_p_t_i_o_n:

     Scores on the 1997 A-level Chemistry examination in Britain. 
     Students are grouped into schools within local education
     authories.  In addition some demographic and pre-test information
     is provided.

_U_s_a_g_e:

     data(Chem97)

_F_o_r_m_a_t:

     A data frame with 31022 observations on the following 8 variables.

     _l_e_a Local Education Authority - a factor

     _s_c_h_o_o_l School identifier - a factor

     _s_t_u_d_e_n_t Student identifier - a factor

     _s_c_o_r_e Point score on A-level Chemistry in 1997

     _g_e_n_d_e_r Student's gender

     _a_g_e Age in month, centred at 222 months or 18.5 years

     _g_c_s_e_s_c_o_r_e Average GCSE score of individual.

     _g_c_s_e_c_n_t Average GCSE score of individual, centered at mean.

_D_e_t_a_i_l_s:

     This data set is relatively large with 31,022 individuals in 2,280
     schools.  Note that while this is used, illustratively, to fit
     Normal response models, the distribution of the response is not
     well described by a Normal distribution.

_S_o_u_r_c_e:

     <URL: http://multilevel.ioe.ac.uk/softrev/chem97.html>

_R_e_f_e_r_e_n_c_e_s:

     Yang, M., Fielding, A. and Goldstein, H. (2002). Multilevel
     ordinal models for examination grades (submitted to _Statistical
     Modelling_).

_E_x_a_m_p_l_e_s:

     str(Chem97)
     summary(Chem97)
     (fm1 <- lmer(score ~ (1|school) + (1|lea), Chem97))
     (fm2 <- lmer(score ~ gcsecnt + (1|school) + (1|lea), Chem97))

