influencPlot               package:car               R Documentation

_R_e_g_r_e_s_s_i_o_n _I_n_f_l_u_e_n_c_e _P_l_o_t

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

     This function creates a "bubble" plot of studentized residuals by
     hat values, with the areas of the circles representing the
     observations proportional to Cook's distances. Vertical reference
     lines are drawn at twice and three times the average hat value,
     horizontal reference lines at -2, 0, and 2 on the
     studentized-residual scale.

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

     influencePlot(model, ...)

     ## S3 method for class 'lm':
     influencePlot(model, scale = 10, col = c(1, 2), labels = names(rstud), 
       identify.cex=par("cex"), identify.col=par("col"), ...)

_A_r_g_u_m_e_n_t_s:

   model: a linear or generalized-linear model.

   scale: a factor to adjust the size of the circles.

     col: colors for plotting points that do not and do have noteworthy
          Cook's distances.

  labels: if 'FALSE' do not identify points interactively with the
          mouse; otherwise a vector of observation labels.

identify.cex, identify.col: aguments to be passed to 'identify'.

     ...: arguments to pass to the 'plot' function.

_V_a_l_u_e:

     Returns the indices of identified points.

_N_o_t_e:

     This function used to be named 'influence.plot'; the name was
     changed to avoid confusion with the 'influence' generic function.

_A_u_t_h_o_r(_s):

     John Fox jfox@mcmaster.ca

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

     J. Fox (2002)  _An R and S-PLUS Companion to Applied Regression_.
     Sage.

_S_e_e _A_l_s_o:

     'cookd', 'rstudent', 'hatvalues'

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

         ## Not run: 
         influencePlot(lm(prestige ~ income + education, data=Duncan))
         
     ## End(Not run)

