UPpivotal              package:sampling              R Documentation

_P_i_v_o_t_a_l _s_a_m_p_l_i_n_g

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

     Select an unequal probability sample by means of  the pivotal
     method (unequal probabilities, without replacement, fixed sample
     size).

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

     UPpivotal(pik,eps=1e-6)

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

     pik: vector of prescribed inclusion probabilities.

     eps: the control value, by default equal to 1e-6.

_D_e_t_a_i_l_s:

     Return a vector (with elements 0 and 1) of size N, where N is the
     population size.   Each element k of this vector indicates the
     status of the unit k  (1, the unit k is selected in the sample; 0,
     otherwise). The value eps is used to control pik (pik>eps & pik <
     1-eps).

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

     Deville, J.-C. and Till, Y. (1998),  Unequal probability sampling
     without replacement through a splitting method,  _Biometrika_,
     85:89-101.
      Chauvet, G. and Till, Y. (2006). A fast algorithm of balanced
     sampling. _to appear in Computational Statistics_.
      Till, Y. (2006), _Sampling Algorithms_, Springer.

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

     'UPrandompivotal'

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

     #define the prescribed inclusion probabilities
     pik=c(0.2,0.7,0.8,0.5,0.4,0.4)
     #select a sample
     s=UPpivotal(pik)
     #the sample is
     (1:length(pik))[s==1]

