當品質特徵來自一個偏態分配時，本論文針對調整的加權標準差R 管制圖、加權變異數R 管制圖和偏態修正的R 管制圖進行數值研究及比較。在考慮製程分配為Weibull、gamma和lognormal分配下。本論文比較上述三種不同的R 管制圖的型一誤差與名目值0.27%的接近程度。當製程資料來自平均數已知的指數分配時，研究的結果顯示調整的加權標準R 管制圖不論在型一誤差及型二誤差都比其他的兩個R 管制圖接近真值。 The thesis conducts a numerical study in comparing the performance of the adjusted weighted standard deviation R chart, weighted variance R chart, and the skewness correlation R chart with the underlying distribution of quality characteristic is skewed. Assume that the underlying distribution is Weibull, gamma, and lognormal, we compare the Type I Risk of those R chart how to be close to the nominal value 0.27%. If the process distribution is exponential with known mean, we show that not only the Type I Risk, but also the Type II Risk of the adjusted weighted standard deviation R chart are closer to those of the exact R chart than both weighted variance R chart and skewess correlation R chart.
