In the first stage of selection, blocks were selected with probabilities proportionate to Census 2000 (U.S. Census Bureau 2000) counts of households.
Haplotype blocks were selected with Haploview [ 39] by considering LD blocks.
Haplotype blocks were selected with Haploview software by considering linkage disequilibrium (LD) blocks.
Tagging SNPs across the blocks were selected with a minor allele frequency (MAF) > 0% and r = 0.8 and were enriched with proxies for known susceptibility SNPs (rs6920220 and rs10499194).
Two blocks in each district and two HSCs in each block were selected in consultation with district- and block-level officials.> As one of the parameters for this study was data quality, a DQA was carried out in each of the districts for a random sample of pregnant women and children in December 2012.
Prepared and numbered envelopes (six assignments per block) were selected consecutively for group assignment, with a single draw for twins.
A stratified, multi-stage sampling scheme was used in six Mexican cities (Mexico City, Guadalajara, Monterrey, Puebla, Tijuana and Mérida) and five Uruguayan cities (Montevideo, Salto, Maldonado, Durazno and Rivera), wherein census tracts and then block groups were selected with probability proportional to the number of households.
From each sampled block, 21 households were selected with equal probability, through systematic sampling, in order to achieve the calculated sample size of 950.
A formalin-fixed, paraffin-embedded block was selected from each patient with Hodgkin lymphoma for immunohistochemical study.
From these blocks, households to be interviewed were selected with equal probability using a systematic sampling procedure.
