Akdeniz, F. and Kaciranlar, S. (1995), On the almost unbiased generalized Liu estimator and unbiased estimation of the Bias and MSE. Comm. Statist. Theo. Meth., 24(7), 1789-1797. Arashi, M., Janfada, M. and Norouzirad, M. (2015), Singular ridge regression with stochastic constrains. Comm. Statist. Theo. Meth., 44, 1281-1292. Bancroft, T. A. (1944), On biases in estimation due to use of preliminary tests of significance. Ann. Math. Statist., 15, 190-204. Khan, S., Saleh, A. K. Md. Ehsanes (1997), Shrinkage pre-test estimator of the intercept parameter for a regression model with multivariate student-t errors. Biom. J., 39, 1-17. Kibria, B.M.G. (1996), On shrinkage ridge regression estimators for restricted linear models with multivariate t disturbances. Students, 1(3), 177-188. Kibria, B. M. G. (2003), Performance of some new ridge regression estimators. Comm. Statist. Sim. Comp., 32, 419-435. Kibria, B. M. G. and Saleh, A. K. Md. Ehsanes (2004), Preliminary test ridge regression estimators with student’s t errors and conflicting test-statistics. Metrika, 59, 105-124. Kuran, O and Ozkale, M. R. (2016), Gilmour’s approach to mixed and stochastic restricted ridge predictions in linear mixed models. Lin. Alg. Appl., 508, 22-47. Li, Y. andYang, H. (2010),Anew ridge-type estimator in stochastic restricted linear regression. Statistics, 45, 123-130. Liu, K. (1993), A new class of biased estimate in linear regression. Comm. Statist. Theo. Meth., 22, 393-402. Ozkale, M. R. (2009), A stochastic restricted ridge regression estimator. J. Mult. Anal., 100, 1706-1716. Roozbeh, M. (2015), Shrinkage ridge estimators in semi parametric regression models. J. Mult. Anal., 136, 56-74. Saleh, A. K. Md. Ehsanes. (2006), Theory of Preliminary Test and Stein-Type Estimation with Application. John Wiley, New York. Saleh, A. K. Md. Ehsanes and Sen, P. K. (1978), Non-parametric estimation of location parametric after a preliminary test regression. Ann. Statist., 6, 154-168. Tabatabaey, S. M. M., Saleh, A. K. Md. Ehsanes, Kibria, B. M. G. (2004), Estimation strategies for parameters of the linear regression model with spherically symmetric distributions. J. Statist. Res., 38(1), 13-31. Ullah, A., Zinde-Walsh, V. (1984), On the robustness of LM, LR and W Tests in Regression Model. Econometrica, 52, 1055-1066. Woods, H., Steinour, H., Starke, H. R. (1932), Effect of composition of Portland cement on heat evolved during hardening. Indust. Eng. Chem., 24, 1207-1241. Yang, H., Chang, X. F. and Liu, D. (2009), Improvement of the Liu estimator in weighted mixed regression. Comm. Statist. Theo. Meth., 38, 285-292. Yang H. and Xu J. (2011), Preliminary test Liu estimators based on the conflictingW, LR and LM tests in a regression model with multivariate student-t error. Metrika, 73(3), 275-292. Yang H. andXuJ. (2009), Analternative stochastic restricted Liu estimator in linear regression. Stat. Papers, 50(3), 639-647. Yang, H. and Wu, J. (2012), A stochastic restricted k-d class estimator. Statistics, 46(6), 759-766. Zellner, A. (1962), An efficient tests for aggregation bias. J. Amer. Statist. Assoc., 57, 348-368.