| The SURVEYSELECT Procedure |
If you specify the option METHOD=PPS_WR, PROC SURVEYSELECT
selects units with probability proportional to size and with
replacement. The procedure makes nh independent random
selections from the stratum of Nh units, selecting with
probability Zhi = Mhi/Mh · .
Because units are selected
with replacement, a unit can be selected for the sample more
than once. The expected number of selections or hits for
unit i in stratum h equals nh Zhi .
If you request the JTPROBS option, PROC SURVEYSELECT computes
the joint expected number of hits for all pairs of selected units
in each stratum. The joint expected number of hits for
units i and j in stratum h equals
-
Ph(ij) = [(nh (nh - 1))/2] Zhi Zhj
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
