本文利用子群資料，在樣本大小適中與考慮變動樣本大小時，以標準差σ 之較佳估計式，分別推導出Cpp 指標的信賴上界和最大臨界值。並以此做為決策的準則，提供一套製程能力的檢驗程序，以判斷製程是否合乎能力水準。 In this paper we use a better estimator of the standard deviation σ based on subsamples for moderate large sample size and variable sample size), to construct the upper confidence bounds and the maximum critical values of the process index Cpp respectively. The test procedures for check if the process meets the capability requirement are also provided.
