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Kukla Degiskenlerin T Istatistigi ile Aykiri Gozlemler Tespit Edilemez


  • Arzdar KIRACI

    () (Baskent University)


In the current literature, in order to be able to detect a single observation as an outlier observation, this observation is represented by a dummy variable and the dummy variable is checked for statistical significance. For an observation to be an outlier observation, the thesis of significant t-statistics of dummy variable is used. This paper proves using a theoretic proof for simple regression model that this thesis is wrong and refutes this thesis using a counterexample. The example derived for this paper illustrates that an outlier observation detected by robust regression methods cannot be detected by the t-statistics of dummy variable. In addition, the effect of adding a dummy variable to regression on important regression statistics is investigated.

Suggested Citation

  • Arzdar KIRACI, 2011. "Kukla Degiskenlerin T Istatistigi ile Aykiri Gozlemler Tespit Edilemez," Istanbul University Econometrics and Statistics e-Journal, Department of Econometrics, Faculty of Economics, Istanbul University, vol. 15(1), pages 1-14, November.
  • Handle: RePEc:ist:ancoec:v:15:y:2011:i:1:p:1-14

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    References listed on IDEAS

    1. Rose, Andrew K. & Yellen, Janet L., 1989. "Is there a J-curve?," Journal of Monetary Economics, Elsevier, vol. 24(1), pages 53-68, July.
    2. Kwiatkowski, Denis & Phillips, Peter C. B. & Schmidt, Peter & Shin, Yongcheol, 1992. "Testing the null hypothesis of stationarity against the alternative of a unit root : How sure are we that economic time series have a unit root?," Journal of Econometrics, Elsevier, vol. 54(1-3), pages 159-178.
    3. Dickey, David A & Fuller, Wayne A, 1981. "Likelihood Ratio Statistics for Autoregressive Time Series with a Unit Root," Econometrica, Econometric Society, vol. 49(4), pages 1057-1072, June.
    4. Bahmani-Oskooee, Mohsen, 1991. "Is there a long-run relation between the trade balance and the real effective exchange rate of LDCs?," Economics Letters, Elsevier, vol. 36(4), pages 403-407, August.
    5. Johansen, Soren & Juselius, Katarina, 1990. "Maximum Likelihood Estimation and Inference on Cointegration--With Applications to the Demand for Money," Oxford Bulletin of Economics and Statistics, Department of Economics, University of Oxford, vol. 52(2), pages 169-210, May.
    6. Josef Brada & Ali Kutan & Su Zhou, 1997. "The exchange rate and the balance of trade: The Turkish experience," Journal of Development Studies, Taylor & Francis Journals, vol. 33(5), pages 675-692.
    7. M. Hashem Pesaran & Yongcheol Shin & Richard J. Smith, 2001. "Bounds testing approaches to the analysis of level relationships," Journal of Applied Econometrics, John Wiley & Sons, Ltd., vol. 16(3), pages 289-326.
    8. Granger, C. W. J. & Newbold, P., 1974. "Spurious regressions in econometrics," Journal of Econometrics, Elsevier, vol. 2(2), pages 111-120, July.
    9. Tihomir P Stucka, 2004. "The Effects of Exchange Rate Change on the Trade Balance in Croatia," IMF Working Papers 04/65, International Monetary Fund.
    10. Johansen, Soren, 1995. "Likelihood-Based Inference in Cointegrated Vector Autoregressive Models," OUP Catalogue, Oxford University Press, number 9780198774501, June.
    11. Engle, Robert & Granger, Clive, 2015. "Co-integration and error correction: Representation, estimation, and testing," Applied Econometrics, Publishing House "SINERGIA PRESS", vol. 39(3), pages 106-135.
    12. Mohsen Bahmani-Oskooee, 2001. "Nominal and real effective exchange rates of middle eastern countries and their trade performance," Applied Economics, Taylor & Francis Journals, vol. 33(1), pages 103-111.
    13. Zelal Kotan & Mesut Saygili, 1999. "Estimating an Import Function for Turkey," Discussion Papers 9909, Research and Monetary Policy Department, Central Bank of the Republic of Turkey.
    14. Goldstein, Morris & Khan, Mohsin S., 1985. "Income and price effects in foreign trade," Handbook of International Economics,in: R. W. Jones & P. B. Kenen (ed.), Handbook of International Economics, edition 1, volume 2, chapter 20, pages 1041-1105 Elsevier.
    15. Gulbin Sahinbeyoglu & Bulent Ulasan, 1999. "An Empirical Examination of the Structural Stability of Export Function : The Case of Turkey," Discussion Papers 9907, Research and Monetary Policy Department, Central Bank of the Republic of Turkey.
    16. Rose, Andrew K., 1990. "Exchange rates and the trade balance : Some evidence from developing countries," Economics Letters, Elsevier, vol. 34(3), pages 271-275, November.
    17. Bardsen, Gunnar, 1989. "Estimation of Long Run Coefficients in Error Correction Models," Oxford Bulletin of Economics and Statistics, Department of Economics, University of Oxford, vol. 51(3), pages 345-350, August.
    18. Elif Akbostanci, 2004. "Dynamics of the Trade Balance: The Turkish J-Curve," Emerging Markets Finance and Trade, Taylor & Francis Journals, vol. 40(5), pages 57-73, September.
    19. M. Faruk Aydin & Ugur Ciplak & Eray M. Yucel, 2004. "Export Supply and Import Demand Models for the Turkish Economy," Working Papers 0409, Research and Monetary Policy Department, Central Bank of the Republic of Turkey.
    20. Johansen, Soren, 1988. "Statistical analysis of cointegration vectors," Journal of Economic Dynamics and Control, Elsevier, vol. 12(2-3), pages 231-254.
    21. Hakan Berument & Nergiz Dincer, 2005. "Denomination composition of trade and trade balance: evidence from Turkey," Applied Economics, Taylor & Francis Journals, vol. 37(10), pages 1177-1191.
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    More about this item


    Robust Regression; t-statistics; dummy variable; outlier; refute the thesis; simple regression model; detection problem; example;

    JEL classification:

    • C2 - Mathematical and Quantitative Methods - - Single Equation Models; Single Variables
    • C3 - Mathematical and Quantitative Methods - - Multiple or Simultaneous Equation Models; Multiple Variables
    • C51 - Mathematical and Quantitative Methods - - Econometric Modeling - - - Model Construction and Estimation
    • C52 - Mathematical and Quantitative Methods - - Econometric Modeling - - - Model Evaluation, Validation, and Selection


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