sampfordpi                package:pps                R Documentation

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

     Compute joint inclusion probabilities for Sampford's method of PPS
     sampling

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

     sampfordpi(sizes,n)

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

   sizes: A vector of the sizes of the units in the population

       n: The sample size

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

     Returns  a matrix with the inclusion probability pi(i) for for
     each unit i in the population and with the joint inclusion
     probability pi(i,j) of units i and j in position (i,j) in the
     matrix, where i and j are not equal. Note that the size of the
     matrix is NxN, where N is the population size.

_N_o_t_e:

     The function 'sampford' can be used to select a sample using
     Sampford's method. See the user's guide, pps.pdf, for more
     information.

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

     sizes <- c(9,2,5,17,4,21,15,7,4,11,23,23,14)
     piij <- sampfordpi(sizes,4)
     weights <- 1/diag(piij)  # the weights one would use for estimation

