The present study considered two independent exponential distributions with the hypothesis for testing equivalence of lifetime means or failure rates, and aimed to determine the required uncensored sample size based on power, sampling cost, and censoring proportion simultaneously in the case of right censoring. Approximate sample size formulas with an iterative procedure were proposed and an uncensored sample size allocation ratio was derived to minimize the total cost for a designated power or maximize statistical power for a limit cost. R codes are provided for easy application. The proposed methods are validated in terms of Type I errors and statistical power in a simulation study, and are recommended for the future use.

中文翻译：

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带有右删失的两个指数分布等价测试的样本量计算

本研究考虑了两个独立的指数分布，并使用假设来检验寿命均值或故障率的当量，并旨在在进行正确审查的同时基于功效，抽样成本和审查比例确定所需的未经审查的样本量。提出了具有迭代程序的近似样本量公式，并推导了未经审查的样本量分配比率，以最小化指定功效的总成本或最大化限制成本的统计功效。提供R代码以便于应用。所提出的方法在I类错误和仿真研究中的统计功效方面得到了验证，并建议将来使用。