stratified sampling 分层抽样 将抽样单位按某种特征或某种规则划分为不同的层,然后不同的层中独立、随机地抽取样本 按性别分,按年龄分,按岗位性质分,按学院分等 分层比例问题: 按比例分层抽样 不按比例分层抽样:当需要对不同层次的子总体进行单独研究或比较研究时候,往往采用不按比例分层抽样。 cluster sampling 整...
Define Sample means. Sample means synonyms, Sample means pronunciation, Sample means translation, English dictionary definition of Sample means. n. The value obtained by dividing the sum of a set of quantities by the number of quantities in the set. Also
2.stratified sampling(分成抽样):将总体分成不同的子群,然后对所有的子群进行抽样. 3.systematic sampling(系统抽样):首先将总体中各单位按一定顺序排列,根据样本容量要求确定抽选间隔,然后随机确定起点,每隔一定的间隔抽取一个单位的一种抽样方式. 4.cluster sampling(整群抽样):总体被分为若干群的子总体,每个子总...
整群抽样(cluster sampling) 总体分群,再随机抽取几个群组成样本,群内全部调查。 优点:便于组织、节省经费。 缺点:抽样误差大于单纯随机抽样。 系统抽样 先将总体的观察单位按某一顺序号分成n个部分,再从第一部分随机抽取第k号观察单位,依次用相等间距,从每一部分各抽取一个观察单位组成样本。
Cluster samplingis designed to address problems of a widespread geographical population. Random sampling from a large population is likely to lead to high costs of access. This can be overcome by dividing the population into clusters, selecting only two or three clusters, and sampling from within ...
Cluster sample More cost effective Less efficient (need larger sample to acquire the same level of precision) 非概率抽样 (non-probability sampling) 相对于概率抽样而言 抽取样本时不是依据随机原则,而是根据研 究目的对数据的要求,采用某种方式从总体 21 究目的对数据的要求,采用某种方式从总体 中抽出部分...
This study establishes a new procedure for incorporating effective sample sizes into cluster sampling designs. The first step in this new procedure is to examine the degree of non-independence, the within and between trip variability, and the effective sample sizes of historical cluster samples to ...
整群抽样 cluster sampling 将样品总体中各单位划分为若干样品群,再从各样品群 中随机抽取整群样品。例如,进行产品检验,每隔四小时或八小时抽取一小时生产的全 部产品进行检验。整群抽样的优点是抽样方法简便,缺点是抽取的样本在总体中分布不 均匀,代表性差。
ppt4_SamplingAndSampleDistribution
Cluster samplingis a form of random sampling. Clusters are defined as different subsets of the larger population. Individual samples within the cluster have similar characteristics. Cluster sampling is commonly used when there are large populations that are spread out, making it expensive and time-con...