Groups were assigned and the students came from all over the world, so we made great efforts in the selection of the student groups that we put together.

对来自世界各地的学生,进行分组，我们花了很大力气选择,放在一起的组。

麻省理工公开课 - 媒体、教育、市场课程节选

It wasn't the--in a place where they use the Mediterranean Diet or not -but it was how much did individuals actually follow the Mediterranean Diet and then they looked to see what impact that had on health.

这不是基于某地区是否处于地海式饮食区,而是基于受测个体本身,遵循地中海式饮食的程度进行分组,然后观测其对健康的影响作用

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选