Outliers are data points that lying far away from the main part of a data set and probably not following the assumed model. These data points are often the special points of interest in many practical situations and their identification is the main purpose of the investigation. Moreover, accurate identification of outliers plays an important role in statistical analysis, since they can strongly influence the stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" o:preferrelative="t" o:spt="75" coordsize="21600,21600" , i=1,… ,n , is Mahalanobis distance, MD i = where and S are arithmetic mean and sample covariance matrix. ltr"