Methods: Census method and sampling survey method were both used to investigate the related data of the second-class large medical equipments in Henan province.

方法：采用普查法和抽样调查法相结合，对河南省乙类大型医用设备的相关资料进行了调查。

youdao

Because the 1990 Census undercounted millions of Americans, mostly minorities, the Clinton administration proposed the sampling method as a way of ensuring a more accurate count in 2000.

ECONOMIST: Sampling is wrong: official