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Complex Samples Sampling Wizard
inclusionprobability matrices are 4×4 for these strata, and the Joint_Prob_5_ column is left empty
for these rows. Similarly, strata 3 and5 have 3×3 joint inclusion probability matrices, and stratum
4 has a 5×5 joint inclusionprobability matrix.
The need for a joint probabilities file is seen by perusing the valuesof the joint inclusion
probabilitymatrices. Whenthe sampling method is not a PPS WOR method, the selection of a PSU
is independentof the selection of another PSU, and their joint inclusion probability is simply the
product oftheir inclusion probabilities. In contrast, the joint inclusionprobability for Townships 9
and 10 of County1 is approximately0.11 (see the first case of Joint_Prob_3_ or the third case of
Joint_Prob_1_), or less than theproduct of their individual inclusion probabilities (the product of
the first case of Joint_Prob_1_andthethirdcaseofJoint_Prob_3_is 0.31×0.44=0.1364).
The pollsters will now conduct interviews for the selectedsample. Once the results are
available, you can process the sample with Complex Samples analysis procedures, using the
samplingplan poll.csplan to provide the sampling specifications and poll_jointprob.sav to provide
the needed joint inclusion probabilities.
Related Procedures
The Complex Samples Sampling Wizardprocedure is a useful tool for creating a sampling plan
file and drawing a sample.
Toready a sample for analysis when you do not have access to the sampling plan file, use
the Analysis Preparation Wizard.