Then the estimated values of the depend variable and the residuals are obtained.So we can test heteroscedasticity by analyzing the trend of the squared residuals.

• 因此可以利用局部多项式拟合方法估计回归系数，进而得到因变量的拟合值及残差，然后通过分析残差的平方关于该回归变量的趋势性来检验误差的异方差性。