一、几个基本概念 1.总体、单元和样本目前,我国森林调查中普遍使用抽样调查方法。所谓抽样调查是指从所欲调查的全部对象中抽取一部分对象进行实地调查、然后对全部对象的数量特征作出估计的调查方法。这里全部对象常称为总体,抽取出来的部分对象称为样本,构成总体(样本)并作为调查单位的 First, a few basic concepts 1. Overall, units and samples At present, China’s forest survey commonly used sampling methods. The so-called sample survey refers to all the objects to be investigated from the part of the object to conduct field surveys, and then quantitative characteristics of all objects to make an estimate of the survey method. All the objects here are often called the population, and some of the extracted objects are called samples, which constitute the population (sample) and are used as the unit of investigation