研究人员特别关注了这个城市中高收入亚群体的消费习惯。

Researchers paid special attention to the spending habits of the high-income ___subpopulation in the city.

这项研究专注于分析65岁以上老年人的子群体。

The study focuses on analyzing a ___subpopulation of elderly people aged 65 and above.