Semi2                package:SASmixed                R Documentation

_O_x_i_d_e _l_a_y_e_r _t_h_i_c_k_n_e_s_s_e_s _o_n _s_e_m_i_c_o_n_d_u_c_t_o_r_s

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

     The 'Semi2' data frame has 72 rows and 5 columns.

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

     This data frame contains the following columns:

     _S_o_u_r_c_e a factor with levels '1' and '2' 

     _L_o_t a factor with levels '1' to '8'

     _W_a_f_e_r a factor with levels '1' to '3'

     _S_i_t_e a factor with levels '1' to '3'

     _T_h_i_c_k_n_e_s_s a numeric vector

_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 (Data Set
     4.4).

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

     str(Semi2)
     xtabs(~Lot + Wafer, Semi2)
     if (require("lme4", quietly = TRUE, character = TRUE)) {
       options(contrasts = c(unordered = "contr.SAS", ordered = "contr.poly"))
       ## compare with output 4.13, p. 156
       print(fm1Semi2 <- lmer(Thickness ~ 1 + (1|Lot/Wafer), Semi2))
       ## compare with output 4.15, p. 159
       print(fm2Semi2 <- lmer(Thickness ~ Source + (1|Lot/Wafer), Semi2))
       print(anova(fm2Semi2))
       ## compare with output 4.17, p. 163
       print(fm3Semi2 <- lmer(Thickness ~ Source + (1|Lot/Wafer) + (1|Lot:Source),
                              Semi2))
       ## This is not the same as the SAS model.
     }

