Perhaps the most frequently asked question concerning sampling is, ‘What sample size do we need?’. The answer to this question is influenced by many factors. Here, we consider the progressively type II censoring and respond to this question by considering the cost of experiment for the proportional hazard rate models. Towards this end, we first introduce a cost function and then by minimizing it we discuss the problem of finding optimal sample size. It is assumed that the sample size is a random variable. Some known candidates for the random sample size, namely the degenerate, binomial, and Poisson distributions, are considered and then we find the parameter of them such that the cost of experiment is bounded. To show the usefulness of results, one special case of the PHR model, the one-parameter Rayleigh distribution is considered. Then, numerical computations and simulation studies are reported. Finally, some concluding remarks are presented.

也许关于抽样最常被问到的问题是“我们需要多大的样本量？”。这个问题的答案受很多因素的影响。在这里，我们考虑渐进式 II 审查并通过考虑比例风险率模型的实验成本来回答这个问题。为此，我们首先引入一个成本函数，然后通过最小化它来讨论寻找最佳样本大小的问题。假设样本大小是一个随机变量。考虑随机样本大小的一些已知候选者，即退化、二项式和泊松分布，然后我们找到它们的参数，使得实验成本是有界的。为了显示结果的有用性，考虑了 PHR 模型的一种特殊情况，即单参数瑞利分布。然后，报告了数值计算和模拟研究。最后，提出了一些结论性意见。