The method of least squared suffers a setback when there is multicollinearity and outliers in the linear regression model. In this article, we developed a new estimator to jointly handle multicollinearity and outliers by pooling the following estimators together: the M-estimator, the principal component and the ridge estimator. The new estimator is called the robust r-k estimator and is employed. We established theoretically that the new estimator is better than some of the existing ones. The simulation studies and real-life application supports the efficiency of the new method.
K E Y W O R D SM-estimator, multicollinearity, outliers, principal component, ridge estimator 1 the impact of an outlier on the following: fitted values, the regression coefficient, estimated variance of or the goodness of fit statistics. Outliers are observations that posed a noticeable change on the model estimates. 16 The presence of an outlier in a model affects the efficiency of LSE. 17,18 Robust regression estimator produced more reliable and stable estimates than LSE for linear regression models with outliers. [19][20][21][22][23][24] Examples include the M-estimator that is resistant to an outlier in the y-direction. 19