To test your null hypothesis, you want to know the probability of obtaining a value this extreme under the assumption that it is due to randomsampling variability.
要检验虚假设，需要知道在假设存在随机抽样可变性的情况下获得这么一个极限值的概率。
2
Tests showed that the average yield per mu obtained by typical mode sampling was more close to the average yield per mu actually measured in blank test than that obtained by randomsampling.
试验结果表明，典型众数抽样较同时同地进行的随机抽样平均亩产量更接近空白试验所测得的每亩平均产量。
3
Methods The migrant workers aged 18~60 in one east city were chosen by stratified randomsampling, and surveyed by a questionnaire about knowledge, behavior of AIDS, and blooded to test HIV antibody.