Esra Gökpinar

Testing the equality of several log-normal means based on a computational approach

ABSTRACTIn this study, we propose a new test based on a computational approach to test the equality of several log-normal means. We compare this test with some existing methods in terms of the type-I error rate and power using Monte Carlo simulations for varying values of number of groups and sample sizes. The simulation results indicate that the proposed test could be suggested as a good alternative for testing the equality of several log-normal means.ABSTRACT In this study, we propose a new test based on a computational approach to test the equality of several log-normal means. We compare this test with some existing methods in terms of the type-I error rate and power using Monte Carlo simulations for varying values of number of groups and sample sizes. The simulation results indicate that the proposed test could be suggested as a good alternative for testing the equality of several log-normal means.

Goodness of fit tests for Nakagami distribution based on smooth tests

ABSTRACT Nakagami distribution is one of the most common distributions used to model positive valued and right skewed data. In this study, we interest goodness of fit problem for Nakagami distribution. Thus, we propose smooth tests for Nakagami distribution based on orthonormal functions. We also compare these tests with some classical goodness of fit tests such as Cramer–von Mises, Anderson–Darling, and Kolmogorov–Smirnov tests in respect to type-I error rates and powers of tests. Simulation study indicates that smooth tests give better results than these classical tests give in respect to almost all cases considered.

Çapraz Tasarımlarda Etkilerin Testi için Parametrik ve Parametrik Olmayan Testlerin Karşılaştırılması

Capraz tasarimlar, psikolojik denemeler, tarim, zooloji gibi bircok alanda kullanilan tasarimlardir. Bu tasarimlar daha az orneklem kullanarak daha guclu sonuclar elde etmek amaciyla kullanilirlar. Bu durum, capraz tasarimlarin onemli avantajlarindan biridir. Calismada, capraz tasarimi hakkinda ayrintili bilgi verilmistir. Capraz tasarimda etkilerin analizi icin kullanilan t testi ve Mann Whitney U testi simulasyon yoluyla deneysel I. tip hata oranlari ve guc degerleri bakimindan karsilastirilmistir. Bu amacla farkli ornek caplari, farkli korelasyon katsayilari ele alinmis ve ayrica testlerin performanslari normal ve normal olmayan dagilimlar altinda incelenmistir. Simulasyon sonuclarina gore, normal dagilim altinda t testinin guc degerleri daha yuksek iken, normal olmayan dagilimlar altinda Mann Whitney U testinin guc degerlerinin daha yuksek oldugu gozlenmistir.

A new computational approach test for one-way ANOVA under heteroscedasticity

ABSTRACT This paper proposes a new test statistic based on the computational approach test (CAT) for one-way analysis of variance (ANOVA) under heteroscedasticity. The proposed test was compared with other popular tests according to type I error and power of tests under different combinations of variances, means, number of groups and sample sizes. As a result, it was observed that the proposed test yields better results than other tests in many cases.

Testing equality of variances for several normal populations

ABSTRACTIn this study, we develop a test based on computational approach for the equality of variances of several normal populations. The proposed method is numerically compared with the existing methods. The numeric results demonstrate that the proposed method performs very well in terms of type I error rate and power of test. Furthermore we study the robustness of the tests by using simulation study when the underlying data are from t, exponential and uniform distributions. Finally we analyze a real dataset that motivated our study using the proposed test.ABSTRACT In this study, we develop a test based on computational approach for the equality of variances of several normal populations. The proposed method is numerically compared with the existing methods. The numeric results demonstrate that the proposed method performs very well in terms of type I error rate and power of test. Furthermore we study the robustness of the tests by using simulation study when the underlying data are from t, exponential and uniform distributions. Finally we analyze a real dataset that motivated our study using the proposed test.

A modified Mack–Wolfe test for the umbrella alternative problem

ABSTRACT The Mack–Wolfe test is the most frequently used non parametric procedure for the umbrella alternative problem. In this paper, modifications of the Mack–Wolfe test are proposed for both known peak and unknown peak umbrellas. The exact mean and variance of the proposed tests in the null hypothesis are also derived. We compare these tests with some of the existing tests in terms of the type I error rate and power. In addition, a real data example is presented.