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无编辑摘要
在每一层中，可以应用几种随机试验策略，包括<font color="#ff8000"> '''简单随机试验 Simple randomization''' </font>、<font color="#ff8000"> '''分块随机试验你Blocked randomization''' </font>和<font color="#ff8000"> '''最小化试验 Minimization''' </font>。
在每一层中，可以应用几种随机试验策略，包括<font color="#ff8000"> '''简单随机试验 Simple randomization''' </font>、<font color="#ff8000"> '''分块随机试验你Blocked randomization''' </font>和<font color="#ff8000"> '''最小化试验 Minimization''' </font>。
=== Simple randomization within strata ===
Stratified random sampling is useful and productive in situations requiring different weightings on specific strata. In this way, the researchers can manipulate the selection mechanisms from each strata to amplify or minimize the desired characteristics in the survey result.
分层随机抽样在特定地层需要不同权重的情况下是有用的和有效的。通过这种方式，研究人员可以操纵来自每个阶层的选择机制，以便在调查结果中放大或减少所需的特征。
Simple randomization is considered as the easiest method for allocating subjects in each stratum. Subjects are assigned to each group purely randomly for every assignment. Even though it is easy to conduct, simple randomization is commonly applied in strata that contain more than 100 samples since a small sampling size would make assignment unequal.<ref name=":0" />
Stratified randomization is helpful when researchers intend to seek for associations between two or more strata, as simple random sampling causes a larger chance of unequal representation of target groups. It is also useful when the researchers wish to eliminate confounders in observational studies as stratified random sampling allows the adjustments of covariances and the p-values for more accurate results.
当研究人员试图寻找两个或多个阶层之间的联系时，分层随机化是有帮助的，因为简单的随机抽样会导致目标群体代表性不平等的可能性更大。当研究人员希望在观察研究中消除混杂因素时，这也是有用的，因为分层随机抽样允许调整协方差和 p 值以获得更准确的结果。
Block randomization is commonly used in the experiment with a relatively big sampling size to avoid the imbalance allocation of samples with important characteristics. In certain fields with strict requests of randomization such as clinical trials, the allocation would be predictable when there is no blinding process for conductors and the block size is limited. The blocks permuted randomization in strata could possibly cause an imbalance of samples among strata as the number of strata increases and the sample size is limited, For instance, there is a possibility that no sample is found meeting the characteristic of certain strata.
Block randomization is commonly used in the experiment with a relatively big sampling size to avoid the imbalance allocation of samples with important characteristics. In certain fields with strict requests of randomization such as clinical trials, the allocation would be predictable when there is no blinding process for conductors and the block size is limited. The blocks permuted randomization in strata could possibly cause an imbalance of samples among strata as the number of strata increases and the sample size is limited, For instance, there is a possibility that no sample is found meeting the characteristic of certain strata.