“…By applying empirical influence function and Cook's statistic, they found that group number 5, 3, 13, and 19 were the most influence groups in model. Rasekh (2006) analysed the same data to detect influential observations on the ridge regression estimator using the local influence approach with minor perturbation on variance, six explanatory variables (Na, Al, K,V ,Cr and Mn). By the variance perturbation, He detected that groups 18, 23, 15 and 6 (imported vessels groups) are most influential groups in ridge measurement error regression.…”