2 sentences

1. 计算这组观测值的较差。

   jì​suàn zhè zǔ guān​cè​zhí de jiào​chā.

   Calculate the range for this set of observations.

   Source: Dong Chinese Dictionary

2. 由于空气污染严重，该地区的空气质量较差。

   yóu​yú kōng​qì wū​rǎn yán​zhòng, gāi dì​qū de kōng​qì zhì​liàng jiào​chà.

   Due to severe air pollution, the air quality in the region is relatively poor.

   Source: Dong Chinese Dictionary