Browsing by Author "Qamarul Islam, M."

Now showing 1 - 3 of 3

Citation - WoS: 4
Citation - Scopus: 4
Estimation in Multivariate Nonnormal Distributions With Stochastic Variance Function
(Elsevier Science Bv, 2014) Islam, M. Qamarul; Qamarul Islam, M.
In this paper the problem of estimation of location and scatter of multivariate nonnormal distributions is considered. Estimators are derived under a maximum likelihood setup by expressing the non-linear likelihood equations in the linear form. The resulting estimators are analytical expressions in terms of sample values and, hence, are easily computable and can also be manipulated analytically. These estimators are found to be remarkably more efficient and robust as compared to the least square estimators. They also provide more powerful tests in testing various relevant statistical hypotheses. (C) 2013 Elsevier B.V. All rights reserved.
Citation - WoS: 2
Citation - Scopus: 1
Impact of Exchange Rate and Customs Union on Trade Balance at Commodity Level of Turkey With Eu (15)
(Routledge Journals, Taylor & Francis Ltd, 2011) Islam, M. Qamarul; Yazici, Mehmet; Qamarul Islam, M.
This paper investigates the short-run and long-run impact of exchange rate and customs union on the trade balance at commodity-group level of Turkey with EU (15). Bounds testing approach is employed where a new strategy in the model selection phase is odopted ensuring that optimal model is selected from those models satisfying both diagnostics and cointegration. Results indicate that in the short-run exchange rate matters in determination of trade balance of 13 commodity groups out of 21 and customs union in 8 cases. Pattern of response of trade balance to exchange rate does not suggest a J-curve effect in any of cases. As for the long-run effect, neither exchange rate nor customs union has a statistically significant effect on trade balance of any of commodity groups, suggesting that those significant short-run effects don't last into long-run.
Citation - WoS: 1
Citation - Scopus: 1
Model Selection Uncertainties and Model Averaging in Autoregressive Time Series Models
(Isoss Publ, 2012) Islam, M. Qamarul; Yazıcı, Mehmet; Yazici, Mehmet; Islam, M.Qamarul; Qamarul Islam, M.; İktisat
Selecting the correct lag order is necessary in order to avoid model specification errors in autoregressive (AR) time series models. Here we explore the problem of lag order selection in such models. This study provides an in-depth but easy understanding of the model selection mechanism to the practitioners in various fields of applied research. Several interesting findings are reported and through these the pitfalls of the model selection procedures are exposed. In particular, we show that the whole exercise of model selection and subsequent statistical inference invariably depends upon unknown entities, namely the true values of parameters in the model. The model averaging technique is proposed as an alternative to the common practice of model selection and it is shown that, as a result, the properties of post-model-selection estimates substantially improve.