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SAS FAQ 
How do I analyze survey data with a stratified design with certainty PSUs?

This example is taken from Lehtonen and Pahkinen's Practical Methods for Design and Analysis of Complex Surveys.

page 60 Table 2.8  Estimates under a PPSSYS  design (n = 8); the Province'91 population.
NOTE:  The certainty PSU (the first line of the data) was entered twice and the weight was changed from 1 to .5 for each observation.  This is necessary because you need to have two observations in each strata.

data page60;
  input id str clu wt hou85 ue91 lab91;
  fpc = 32;
  cards;
  1 2 1 0.5 26881 4123 33786
  2 2 1 0.5 26881 4123 33786
  3 1 10 1.004 9230 1623 13727
  4 1 4 1.893 4896 760 5919
  5 1 7 2.173 4264 767 5823
  6 1 32 2.971 3119 568 4011
  7 1 26 4.762 1946 331 2543
  8 1 18 6.335 1463 187 1448
  9 1 13 13.730 675 129 927
  ;
run;

proc sort data = page60;
  by str;
run;

proc surveymeans data = page60 sum std;
  weight wt;
  strata str;
  cluster clu;
  var ue91;
run;

The SURVEYMEANS Procedure

            Data Summary

Number of Strata                   2
Number of Clusters                 8
Number of Observations             9
Sum of Weights                33.868

               Statistics

Variable             Sum         Std Dev
----------------------------------------
ue91               15077      521.121241
----------------------------------------

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