Robust ridge methods based on M, S, MM and GM estimators are examined in the presence of multicollinearity and outliers. GM Walker, using the LS estimator as the initial estimator is used. S and MM estimators are also used as initial estimators with the aim of evaluating the two alternatives as biased robust methods.

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Parallel to the rapid developments in technology, a rapid change has been experienced in communication tools as well. As a result, smart phones can now perform a number of computer procedures besides allowing ordinary telephone conversations. Today, it is seen that smart phone use is quite common especially among young people. The present study focuses on smart phone users' levels of satisfaction with smart phones and on the factors likely to be influential on their satisfaction levels. For this purpose, the related research data were collected with a questionnaire conducted in Eskisehir, and factor analysis was carried out to determine the factors regarding the participants' attitudes towards smart phone use. Lastly, with the help of logistic regression analysis, a mathematical model was developed to determine the smart phone users' satisfaction levels.

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