1## check poisson sampling
2library(survey)
3data(api)
4set.seed(2021-7-15)
5apipop$prob<-apipop$api00/1000
6insample<-rbinom(nrow(apipop),1,apipop$prob)
7apipois<-apipop[insample,]
8des<-svydesign(id=~1, prob=~prob, pps=poisson_sampling(apipois$prob), data=apipois)
9
10stopifnot(isTRUE(all.equal(
11 as.vector(SE(svytotal(~api00,design=des))),
12 as.vector(sqrt(sum( (apipois$api00*weights(des))^2*(1-apipois$prob))))
13 )))
14