As a subject matter expert in statistics, I can explain the terms PP and PPK, which are related to statistical process control and quality management.

PP (Performance Probability) is a statistical measure that represents the likelihood that a process will produce a conforming unit. It is calculated by taking the number of conforming units divided by the total number of units produced. In other words, it's the proportion of non-defective items out of the total items produced.

**PPK (Performance Process Capability Index)** is a statistical index that measures the process capability based on the actual performance of the process. It is calculated by taking the square root of the PP value. PPK is used to assess the potential of a process to produce items within specification limits when the process is in control. A PPK value greater than 1 indicates that the process is capable of producing items within the specified limits.

Here's the translation in Chinese:

作为统计学领域的专家，我可以解释PP和PPK这两个术语，它们与统计过程控制和质量管理有关。

PP（性能概率）是一个统计度量，代表一个过程产生合格单元的可能性。它通过将合格单元数除以总生产单元数来计算。换句话说，它是生产的总项目中无缺陷项目的比例。

PPK（性能过程能力指数）是一个统计指数，基于过程的实际性能来衡量过程能力。它通过取PP值的平方根来计算。PPK用于评估过程在受控状态下产生符合规格限制的项目潜力。PPK值大于1表明过程能够生产出符合指定限制的项目。

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Sorry to tell, but definition of Cpk and Ppk is wrong, it��s just the other way round: Ppk is a short term analysis (mostly done with 50 or 100 samples measured) Ppk is Process Potential Capability. Cpk is long term analysis and is Continous Process capability.read more >>