MTH-416, REGRESSION ANALYSIS Lecture Notes - Lecture 16: Linear Regression, Confidence Interval, Bias Of An Estimator
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Application of ols fails in case of autocorrelation in the data and leads to serious consequences as. Usual t -ratio and f ratio tests provide misleading results. Since disturbances are nonspherical, so generalized least squares estimate of yields more efficient estimates than olse. The glse is best linear unbiased estimator of . The durbin-watson (d-w) test is used for testing the hypothesis of lack of the first-order autocorrelation in the disturbance term. Use ols to estimate in y x. 2(1 r r where r is the sample autocorrelation coefficient from residuals based on olse and can be regarded as the regression coefficient of. Here te on positive autocorrelation of negative autocorrelation of. 2d te "s te "s d . So r if 1 if 0 r. ,x so for different data sets, different values of d are obtained. Since e depends on distribution of d depends on x .