Significados de stratified sample en inglés

Design of study: Randomised controlled trial in a stratified sample.

Methods: A stratified sample of 184 patients with primary sclerosing cholangitis and age- and sex-matched institutional control subjects were identified.

Objective: In 2016, data were collected and analyzed from a nationally representative stratified sample of 816 LHDs.

Using this as our sampling frame, we conducted questionnaire surveys with a stratified sample of 1,924 household heads and 945 household heads' wives.

Methods: A randomized and stratified sample of 47,979 students from state and private schools of the 27 Brazilian state capitals completed a self-report questionnaire.