observational study的用法和樣例：
例句
- Pacifier use was associated with reduced duration of breast-feeding in most observational studies.
在多數觀察研究中，使用安撫奶嘴與減少母乳哺喂期間有關。 - This was an observational study and therefore treatment strategy was not randomised but left to the discretion of the individual doctor or the patient.
這是一個觀察研究，而且治療策略也不隨機，但它留給醫生或患者很多思考。
