As scientists, they'd been trained to draw statistical conclusions from a repeated experiment, and use percentages to describe their certainty about the results. (slate.com)
A 1961 study in the American Journal of Public Health on 611 pregnant women found that those with a flu infection were more likely to have had a miscarriage, a stillbirth or a preterm delivery than those with no infection (though the number of women uninfected was too low to draw firm statistical conclusions). (livescience.com)
With enough such discoveries, researchers could reach statistical conclusions and build up a big picture of trade routes, migration and warfare throughout history (scientificamerican.com)