wood               package:robustbase               R Documentation

_M_o_d_i_f_i_e_d _D_a_t_a _o_n _W_o_o_d _S_p_e_c_i_f_i_c _G_r_a_v_i_t_y

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

     The original data are from Draper and Smith (1966) and were used
     to determine the influence of anatomical factors on wood specific
     gravity, with five explanatory variables and an intercept. These
     data were contaminated by replacing a few observations with
     outliers.

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

     data(wood)

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

     A data frame with 20 observations on the following 6 variables.

     _x_1, _x_2, _x_3, _x_4, _x_5 explanatory "anatomical" wood variables.

     _y wood specific gravity, the target variable.

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

     Draper and Smith (1966, p.227)

     Peter J. Rousseeuw and Annick M. Leroy (1987) _Robust Regression
     and Outlier Detection_ Wiley, p.243, table 8.

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

     data(wood)
     plot(wood)
     summary( lm.wood <-        lm(y ~ ., data = wood))
     summary(rlm.wood <- MASS::rlm(y ~ ., data = wood))
     summary(lts.wood <-    ltsReg(y ~ ., data = wood))

     wood.x <- as.matrix(wood)[,1:5]
     c_wood <- covMcd(wood.x)
     c_wood

