Tolong jelaskan mengenai and dari Studentized residual dalam bahasa sunda

(Here  is the ith error, and  is the ith residual.)  Moréover, the residuals, unlike the errors, do not all have the same variance: the variance incréases as the corresponding x-value gets farther from the average x-value.  The fact that the variances of the residuals differ, even though the variances of the true errors are all equal to éach other, is the principal réason for the need for Studentization.