在1983年，R. Dennis Cook & Sanford Weisberg 對於常數變異數這個假設提出了一個檢定方法。他們利用分數檢定來檢定模型是否符合此假設，並用圖形來加以輔助，不過並未加以證明。
在此篇論文中，我們嘗試證明他們在當時所做出來的結果，並提供SAS的程式。 In using Regression model, we have to support these three basic assumptions which in Regression. They are (1) Independence, (2) Normality, and (3) Constant Variance. And many scholars provide several diagnostic techniques for each assumption.
In 1983, R. Dennis Cook & Sanford Weisberg were given a diagnostic method for checking the assumption of constant variance. They try to use the score test to test if the model satisfies the assumption or not. And use the graphic to complement the score test.But without prove all of the result.
In this dissertation, we try to prove the result that they did in 1983.
