width.SJ                package:MASS                R Documentation

_B_a_n_d_w_i_d_t_h _S_e_l_e_c_t_i_o_n _b_y _P_i_l_o_t _E_s_t_i_m_a_t_i_o_n _o_f _D_e_r_i_v_a_t_i_v_e_s

_D_e_s_c_r_i_p_t_i_o_n:

     Uses the method of Sheather & Jones (1991) to select the bandwidth
     of a Gaussian kernel density estimator.

_U_s_a_g_e:

     width.SJ(x, nb = 1000, lower, upper, method = c("ste", "dpi"))

_A_r_g_u_m_e_n_t_s:

       x: a numeric vector 

      nb: number of bins to use. 

upper, lower: range over which to search for solution if 'method =
          "ste"'. 

  method: Either '"ste"' ("solve-the-equation") or '"dpi"' ("direct
          plug-in"). 

_V_a_l_u_e:

     a bandwidth.

_R_e_f_e_r_e_n_c_e_s:

     Sheather, S. J. and Jones, M. C. (1991) A reliable data-based
     bandwidth selection method for kernel density estimation. _Journal
     of the Royal Statistical Society series B_ *53*, 683-690.

     Scott, D. W. (1992) _Multivariate Density Estimation: Theory,
     Practice, and  Visualization._ Wiley.

     Wand, M. P. and Jones, M. C. (1995) _Kernel Smoothing._ Chapman &
     Hall.

_S_e_e _A_l_s_o:

     'ucv', 'bcv', 'density'

_E_x_a_m_p_l_e_s:

     attach(geyser)
     width.SJ(duration, method = "dpi")
     width.SJ(duration)
     detach()

     width.SJ(galaxies, method = "dpi")
     width.SJ(galaxies)