The preliminary test ridge regression estimators (P T R R E) based on the Wald (W), Likelihood Ratio (L R) and Lagrangian Multiplier (L M) tests for estimating the regression parameters has been considered in this paper. Here we consider the multiple regression model with student t error...

This paper combines the idea of preliminary test and ridge regression methodology, when it is suspected that the regression coefficients may be restricted to a subspace. The preliminary test ridge regression estimators (PTRRE) based on the Wald (W), Likelihood Ratio (LR) and Lagrangian...

The zero inflated Poisson regression model is very common when analysing economic data that comes in the form of non-negative integers since it accounts for excess zeros and over-dispersion of the dependent variable. This model may be used in innovation analysis to see for example the impact on...

In this paper we have reviewed some existing and proposed some new estimators for estimating the ridge parameter "k" . All in all 19 different estimators have been studied. The investigation has been carried out using Monte Carlo simulations. A large number of different models were investigated...