All sampling functions in sondage return objects inheriting from class
"sondage_sample". These objects store the realized sample together with
the design-defining quantities needed by the query generics.
Details
All sondage_sample objects contain:
$sampleSample indices (integer vector, or matrix/list when
nrep > 1).$nTarget or expected sample size.
$NPopulation size.
$methodSampling method name.
$fixed_sizeWhether the sample size is fixed by design.
Without-replacement ("wor") objects also contain:
$pikInclusion probability vector. For most methods this equals the true first-order probabilities. For
"sps"and"pareto", this is the target vector.
With-replacement ("wr") objects also contain:
$probPer-draw selection probability vector.
$hitsRealized selection counts (integer vector, or
N x nrepmatrix whennrep > 1).
The class vector records the design family:
c("equal_prob", "wor", "sondage_sample")Equal probability, without replacement.
c("equal_prob", "wr", "sondage_sample")Equal probability, with replacement.
c("unequal_prob", "wor", "sondage_sample")Unequal probability, without replacement (includes balanced).
c("unequal_prob", "wr", "sondage_sample")Unequal probability, with replacement.