The first stage was composed of selecting 30 enumeration areas (EAs) by using systematic random sampling with selection probability proportional to size using the 1998 census.
Index children were sampled with selection probabilities designed to equally represent strata defined by school, grade, English-speaking versus non-English-speaking homes, and sex.
Both used a nationwide two-stage clustered sample design with selection of study points based on community type and federal state and subsequent sampling of persons aged 18 79 years stratified by sex and age group from the local population registers [ 17, 18].
The VSKT was initially sampled in 1983 as a stratified6 random sample with disproportional selection probabilities and since then has continued as a panel containing monthly information on the individuals included in the sample.
This difference may be due to different hospital sizes, as university hospitals were more frequent in the EPIC sample (35%) and ICUs participated by invitation, in contrast to our representative sample with random selection of ICUs.
The urban and rural areas were identified as the main sampling strata with selection done in two stages.
At upper secondary level of education, the survey adopted and countries adhered to a probabilistic two-stages cluster sampling design with selection of schools (at Stage 1) and of teachers within schools (at Stage 2) (OECD 2013a, b, 2014a, b).
Messenger RNA for 759 and SCRAM samples was isolated from total RNA samples with polyA selection, size selected and prepared into sequencing libraries with the TruSeq RNA sample preparation workflow from Illumina (San Diego, CA).
In addition, two exponential models, namely, with sample selection, without sample selection, were developed.
For comparison, three additional LSSVR models, namely, only with sample selection, only with improved color vector angle, without sample selection or improved color vector angle, were developed.
