Of course, most pollsters try to correct for differences in sample composition by weighting samples to reflect population demographics. (today.yougov.com)
«It's illustrating the impact of sample composition on these measures,» Mills says. (sciencenews.org)
«In epidemiology we think about sample composition a lot,» notes Kaja LeWinn, an epidemiologist at the University of California in San Francisco. (sciencenews.org)