PPS Sampling
Randomize units within strata
Select one unit with PPS
PPS systematic sampling
Stratified PPS systematic sampling
PPS sampling with replacement
Sampford's PPS sampling method
Joint inclusion probabilities for Sampford's PPS sampling method
Check that unit sizes are not too big
Stratified simple random sampling
Compute size of each stratum
Functions to select samples using PPS (probability proportional to size) sampling. The package also includes a function for stratified simple random sampling, a function to compute joint inclusion probabilities for Sampford's method of PPS sampling, and a few utility functions. The user's guide pps-ug.pdf is included in the .../pps/doc directory. The methods are described in standard survey sampling theory books such as Cochran's "Sampling Techniques"; see the user's guide for references.