random sample

A random sample ensures that every member of the population has an equal probability of being selected.随机样本确保了总体中的每个成员都有相同的概率被选中。

Drawing a truly random sample from large populations can be logistically challenging and costly.从庞大的人口中抽取真正的随机样本在后勤上可能具有挑战性且成本高昂。