由實驗所得之雙向分類的反應值，常因人為記錄的疏忽，或是儀器設備的測量誤差，也可能是某些潛在因素，帶來了一些有問題的觀察值，這些問題點的存在，可能會與其他資料點有明顯的距離差異或位置偏離，同時亦可能會影響模型之參數估計，導致研究者選擇了不當的模型，為了避免此缺憾，本文乃針對雙向分類之反應值被刪去一個或二個的情況下，導出AP及Cook統計量的公式，在進行模式選擇之前，利用這二個統計量，先對所蒐集到的資料做一番診斷，以便找出離群值或是對參數估計有影響力的觀察值。當然，本文診斷雙向分類中有影響力觀察值的探測工作是屬於先驅工作中的一小部分，其目的不在於確認有那些不尋常的點，而是在懷擬那些點可能會有問題，以提供往後分析工作更多的資訊。

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