tolellipse               package:rrcov               R Documentation

_T_o_l_e_r_a_n_c_e _E_l_l_i_p_s_e _P_l_o_t

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

     Plots the 0.975 tolerance ellipse of the bivariate data set 'x'.
     The ellipse is defined by those data points whose distance  is
     equal to the squareroot of the 0.975 chisquare quantile  with 2
     degrees of freedom.

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

     tolellipse(x, mcd, cutoff, id.n, classic = FALSE, tol=1e-7)

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

       x: a two dimensional matrix or data frame. 

     mcd: An object of type mcd - its attributes center and cov will be
          used. If missing the MCD will be computed. 

  cutoff: Distance needed to flag data points outside the ellipse  

    id.n: Number of observations to identify by a label. If not
          supplied, the number of observations with distance larger
          than 'cutoff' is used.  

 classic: Whether to plot the classical distances too. Default is
          'classic'=FALSE. 

     tol: Tolerance to be used for computing the inverse see 'solve'.
          Default is 'tol = 10e-7'

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

     'tolellipse'

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

     data(hbk)
     mcd <- covMcd(hbk.x)       # compute mcd in advance
     tolellipse(hbk.x[,1:2])    # must be a 2-dimensional data set: take the first two columns

